Table of Contents
Can You Drink Tap Water in Napa?
Yes, Napa's tap water is generally considered safe to drink as Napa has no active health based violations of the Safe Drinking Water Act (SDWA) that we are aware of. Other factors such as lead piping in a home, or low levels of pollutants on immunocompromised individuals, should also be considered, however. To find more recent info we might have, you can check out our boil water notice page or the city's water provider website.
According the EPA’s ECHO database, from April 30, 2019 to June 30, 2022, Napa's water utility, City of Napa, had 0 violations of the Safe Drinking Water Act. For more details on the violations, please see our violation history section below. The last violation for Napa was resolved on March 31, 2016. This assessment is based on the City of Napa water system, other water systems in the city may have different results.
While tap water that meets the EPA health guidelines generally won’t make you sick to your stomach, it can still contain regulated and unregulated contaminants present in trace amounts that could potentially cause health issues over the long-run. These trace contaminants may also impact immunocompromised and vulnerable individuals.
The EPA is reviewing if it’s current regulations around pollutant levels in tap water are strict enough, and the health dangers posed by unregulated pollutants, like PFAS.
Water Quality Report for Napa Tap Water
The most recent publicly available numbers for measured contaminant levels in Napa tap water are in its 2020 Water Quality Report. As you can see, there are levels which the EPA considers to be acceptable, but being below the maximum allowable level doesn’t necessarily mean the water is healthy.
Lead in tap water, for example, is currently allowed at up to 15ppb by the EPA, but it has set the ideal goal for lead at zero. This highlights how meeting EPA standards doesn’t necessarily mean local tap water is healthy.
EPA regulations continue to change as it evaluates the long term impacts of chemicals and updates drinking water acceptable levels. The rules around arsenic, as well as, lead and copper are currently being re-evaluated.
There are also a number of "emerging" contaminants that are not currently. For example, PFAS (Per- and polyfluoroalkyl substances), for which the EPA has issued a health advisory. PFAS are called "forever chemicals" since they tend not to break down in the environment or the human body and can accumulate over time.
We recommend looking at the contaminants present in Napa's water quality reports, or getting your home's tap water tested to see if you should be filtering your water.
Napa Tap Water Safe Drinking Water Act Violation History - Prior 10 Years
Below is a ten year history of violations for the water system named City of Napa for Napa in California. For more details please see the "What do these Violations Mean?" section below.
From Jan. 1, 2016 to March 31, 2016, Napa had 1 health-based Safe Drinking Water Act violation with the violation category being Maximum Contaminant Level Violation, more specifically, the violation code was Maximum Contaminant Level Violation, Average which falls into the Disinfectants and Disinfection Byproducts Rule rule code group, and the Stage 2 Disinfectants and Disinfection Byproducts Rule rule code family for the following contaminant code: TTHM.
From Oct. 1, 2015 to Dec. 31, 2015, Napa had 1 health-based Safe Drinking Water Act violation with the violation category being Maximum Contaminant Level Violation, more specifically, the violation code was Maximum Contaminant Level Violation, Average which falls into the Disinfectants and Disinfection Byproducts Rule rule code group, and the Stage 2 Disinfectants and Disinfection Byproducts Rule rule code family for the following contaminant code: TTHM.
From July 1, 2015 to Sept. 30, 2015, Napa had 1 health-based Safe Drinking Water Act violation with the violation category being Maximum Contaminant Level Violation, more specifically, the violation code was Maximum Contaminant Level Violation, Average which falls into the Disinfectants and Disinfection Byproducts Rule rule code group, and the Stage 2 Disinfectants and Disinfection Byproducts Rule rule code family for the following contaminant code: TTHM.
From April 1, 2015 to June 30, 2015, Napa had 1 health-based Safe Drinking Water Act violation with the violation category being Maximum Contaminant Level Violation, more specifically, the violation code was Maximum Contaminant Level Violation, Average which falls into the Disinfectants and Disinfection Byproducts Rule rule code group, and the Stage 2 Disinfectants and Disinfection Byproducts Rule rule code family for the following contaminant code: TTHM.
From Jan. 1, 2015 to March 31, 2015, Napa had 1 health-based Safe Drinking Water Act violation with the violation category being Maximum Contaminant Level Violation, more specifically, the violation code was Maximum Contaminant Level Violation, Average which falls into the Disinfectants and Disinfection Byproducts Rule rule code group, and the Stage 2 Disinfectants and Disinfection Byproducts Rule rule code family for the following contaminant code: TTHM.
Is there Lead in Napa Water?
Based on the EPA’s ECHO Database, 90% of the samples taken from the Napa water system, City of Napa, between sample start date and sample end date, were at or below, 0.0 mg/L of lead in Napa water. This is 0% of the 0.015 mg/L action level. This means 10% of the samples taken from Napa contained more lead.
While Napa water testing may have found 0.0 mg/L of lead in its water, that does not mean your water source has the same amount. The amount of lead in water in a city can vary greatly from neighborhood to neighborhood, or even building to building. Many buildings, particularly older ones, have lead pipes or service lines which can be a source of contamination. To find out if your home has lead, we recommend getting you water tested.
No amount of lead in water is healthy, only less dangerous. As lead accumulates in our bodies over time, even exposure to relatively small amounts can have negative health effects. For more information, please check out our Lead FAQ page.
Are there PFAS in Napa Tap Water?
Currently, testing tap water for PFAS isn’t mandated on a national level. We do have a list of military bases where there have been suspected or confirmed leaks. There appears to be at least one military base - Mare Island NSY - near Napa with suspected leaks.
With many potential sources of PFAS in tap water across the US, the best information we currently have about which cities have PFAS in their water is this ewg map, which you can check to see if Napa has been evaluated for yet.
Our stance is better safe than sorry, and that it makes sense to try to purify the tap water just in case.
Napa SDWA Violation History Table - Prior 10 Years
| Compliance Period | Status | Health-Based? | Category Code | Code | Rule Code | Contaminant Code | Rule Group Code | Rule Family Code |
|---|---|---|---|---|---|---|---|---|
| 01/01/2016 - 03/31/2016 | Resolved | Yes | Maximum Contaminant Level Violation (MCL) | Maximum Contaminant Level Violation, Average (02) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) | TTHM (2950) | Disinfectants and Disinfection Byproducts Rule (200) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) |
| 10/01/2015 - 12/31/2015 | Resolved | Yes | Maximum Contaminant Level Violation (MCL) | Maximum Contaminant Level Violation, Average (02) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) | TTHM (2950) | Disinfectants and Disinfection Byproducts Rule (200) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) |
| 07/01/2015 - 09/30/2015 | Resolved | Yes | Maximum Contaminant Level Violation (MCL) | Maximum Contaminant Level Violation, Average (02) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) | TTHM (2950) | Disinfectants and Disinfection Byproducts Rule (200) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) |
| 04/01/2015 - 06/30/2015 | Resolved | Yes | Maximum Contaminant Level Violation (MCL) | Maximum Contaminant Level Violation, Average (02) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) | TTHM (2950) | Disinfectants and Disinfection Byproducts Rule (200) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) |
| 01/01/2015 - 03/31/2015 | Resolved | Yes | Maximum Contaminant Level Violation (MCL) | Maximum Contaminant Level Violation, Average (02) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) | TTHM (2950) | Disinfectants and Disinfection Byproducts Rule (200) | Stage 2 Disinfectants and Disinfection Byproducts Rule (220) |
What do these Violations Mean?
Safe Drinking Water Act Violations categories split into two groups, health based, and non-health based. Generally, health based violations are more serious, though non-health based violations can also be cause for concern.
Health Based Violations
- Maximum contaminant levels (MCLs) - maximum allowed contaminant level was exceeded.
- Maximum residual disinfectant levels (MRDLs) - maximum allowed disinfectant level was exceeded.
- Other violations (Other) - the exact required process to reduce the amounts of contaminants in drinking water was not followed.
Non-Health Based Violations
- Monitoring and reporting violations (MR, MON) - failure to conduct the required regular monitoring of drinking water quality, and/or to submit monitoring results on time.
- Public notice violations (Other) - failure to immediately alert consumers if there is a serious problem with their drinking water that may pose a risk to public health.
- Other violations (Other) - miscellaneous violations, such as failure to issue annual consumer confidence reports or maintain required records.
SDWA Table Key
| Field | Description |
|---|---|
| Compliance Period | Dates of the compliance period. |
| Status |
Current status of the violation.
|
| Health-Based? | Whether the violation is health based. |
| Category Code |
The category of violation that is reported.
|
| Code | A full description of violation codes can be accessed in the SDWA_REF_CODE_VALUES (CSV) table. |
| Contaminant Code | A code value that represents a contaminant for which a public water system has incurred a violation of a primary drinking water regulation. |
| Rule Code |
Code for a National Drinking Water rule.
|
| Rule Group Code |
Code that uniquely identifies a rule group.
|
| Rule Family Code |
Code for rule family.
|
For more clarification please visit the EPA's data dictionary.
Napa Water - Frequently Asked Questions
| By Phone: | 707-253-0822 |
| By Email: | ekebbas@cityofnapa.org |
| By Mail: | P.O. BOX 660 NAPA, CA, 94559 |
Existing customers can login to their City of Napa account to pay their Napa water bill by clicking here.
If you want to pay your City of Napa bill online and haven't made an account yet, you can create an account online. Please click here to create your account to pay your Napa water bill.
If you don't want to make an account, or can't remember your account, you can make a one-time payment towards your Napa water bill without creating an account using a one time payment portal with your account number and credit or debit card. Click here to make a one time payment.
Moving to a new house or apartment in Napa means you will often need to put the water in your name with City of Napa. In order to put the water in your name, please click the link to the start service form below. Start service requests for water bills typically take two business days.
Leaving your house or apartment in Napa means you will likely need to take your name off of the water bill with City of Napa. In order to take your name off the water bill, please click the link to the stop service form below. Stop service for water bills requests typically take two business days.
The estimated price of bottled water
$1.67 in USD (1.5-liter)
USER SUBMITTED RATINGS
- Drinking Water Pollution and Inaccessibility
- Water Pollution
- Drinking Water Quality and Accessibility
- Water Quality
The above data is comprised of subjective, user submitted opinions about the water quality and pollution in Napa, measured on a scale from 0% (lowest) to 100% (highest).
Related FAQS
Napa Water Quality Report (Consumer Confidence Report)
The EPA mandates that towns and cities consistently monitor and test their tap water. They must report their findings in an annual Consumer Confidence Report. Below is the most recent water quality report from Napa's Water. If you would like to see the original version of the report, please click here.
annualWATER
Quality
REPORT
REPORTING YEAR 2019
Presented By
Este informe contiene información muy importante sobre su agua |
PWS ID#: 2810003 |
potable. Tradúzcalo o hable con alguien que lo entienda bien. |
Our Mission Continues
We are once again pleased to present our annual water quality report covering all testing performed between January 1 and December 31, 2019. We dedicate ourselves to producing drinking water that meets all state and federal standards. We continually strive to adopt new methods for delivering the
conservation, and community education while continuing to serve the needs of all our
water users.
Please remember that we are always available should you ever have any questions or concerns about your water.
Lead in Home Plumbing
If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. Unlike other regions of the U.S. where lead was prevalent, it was not the predominant construction material used in the City of Napa for water service installations. In addition, years of monitoring show that the existing public system pipe network does not contribute lead to our drinking water. Our next lead and copper collection is scheduled for July 2021. The City of Napa is responsible for providing high- quality drinking water, but we cannot control the variety of materials used in plumbing components. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap for 30 seconds to 2 minutes before using water for drinking or cooking. (If you do so, you may wish to collect the flushed water and reuse it for another beneficial purpose, such as watering plants.) If you are concerned about lead in your water, you may wish to have your water tested. Information on lead in drinking water, testing methods, and steps you can take to minimize
exposure is available from the Safe Drinking Water Hotline at (800)
Community Participation
The City of Napa encourages citizens to participate in our City Council meetings, which take place on the first and third Tuesday of each month from 3:30 to 5:00 p.m. and again from 6:30 to 9:00 p.m. in Council Chambers at City Hall, 955 School Street. For more information concerning city activities and Covid-
19 requirements, please see our website at www.cityofnapa.org.
Protecting Your Water
Bacteria are a natural and important part of our world. There are around 40 trillion bacteria living in each of us; without them, we would not be able to live healthy lives.
Coliform bacteria are common in the environment and are generally not harmful themselves. However, the presence of this bacterial form in drinking water is a concern because it indicates the water may be contaminated with other organisms that can cause disease.
In 2016 the U.S. EPA passed a regulation called the Revised Total Coliform Rule, which requires additional steps that water systems must take in order to ensure the integrity of the drinking water distribution system by monitoring for the presence of bacteria like total coliform and E. coli. The rule requires more stringent standards than the previous regulation, and it requires water systems that may be vulnerable to contamination to have in place procedures that will minimize the incidence of contamination. Water systems that exceed a specified frequency of total coliform occurrences are required to conduct an assessment of their system and correct any problems quickly. The U.S. EPA anticipates greater public health protection under this regulation due to its more preventive approach to identifying and fixing problems that may affect public health.
Though we have been fortunate to have the
Important Health Information
Some people may be more vulnerable to contaminants in drinking water than the general population.
Immunocompromised persons such as persons with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly, and infants may be particularly at risk from infections. These people should seek advice about drinking water from their health care providers. The U.S. EPA/CDC (Centers for Disease Control and Prevention) guidelines on appropriate means to lessen the risk of infection by cryptosporidium and other microbial contaminants are available from the Safe Drinking
Water Hotline at (800)
Que stions?
For more information about this report, or for any questions relating to your drinking water, please call Erin Kebbas, Water Quality Manager, at (707)
Protecting Our Watersheds
The City of Napa is devoted to protecting the land surrounding our local source waters in order to maintain the quality and purity of water used for Napa’s drinking water consumers. In the long term, protecting our watersheds is one of the least costly and most important actions we can take to reduce the risk of unwanted constituents in our drinking water. Algal growth due to the addition of nutrients is the number one cause of taste and odor affecting your tap water. Nutrients in the watershed are increased artificially by
wastewater systems as well as fertilizers and runoff from agricultural practices.
Every five years, the City of Napa conducts a source water assessment to evaluate the quality of the water used as drinking water supply and examine activities associated with the specific waterway and surrounding areas to determine their contribution to contamination. These potential contributors are then compiled into a Vulnerability Summary. Results from the Vulnerability Summaries show the most significant potential sources of contaminants for the City of Napa’s source waters are:
Lake Hennessey (completed April 2018): Pacific Union College Wastewater Treatment Plant, vineyards, fires, invasive species, potential hazardous material spills due to traffic accidents (on Highway 128 near lake), septic tank systems (in Angwin), grazing, and wild animals.
Lake Milliken (completed April 2018): Fires, vineyards, grazing, and wild animals.
Sacramento Delta (updated 2017): Recreational use, urban and agricultural runoff, grazing animals, herbicide application, and seawater intrusion.
Copies of the complete assessments are available through the SWRCB DDW, Santa Rosa District Office, 50 D Street, Suite 200, Santa Rosa, CA 95404 or by calling Amy Little, Associate Sanitary Engineer, SWRCB, at (707)
Ensuring Reliability of Your Water During the
Our existing disinfection process that protects your drinking water is effective against the novel coronavirus.
During this pandemic we have taken many precautionary steps to ensure we are able to keep clean, safe water flowing to you. Highlights of precautions we enacted in early March 2020 and continue through the ongoing pandemic include:
- Securing redundancy in key supply chains such as chemicals for water treatment process, repair parts and inventory for our pipe network
- Transitioning engineering and admin staff to work remotely
- Limiting physical interaction with water treatment operators, by restricting entrance to the control room
- Modifying operations to keep water treatment plant operators isolated at the Hennessey Treatment Plant through the end of April after routine maintenance on our State Water Project facilities was completed
- Staggering shift hours to minimize overlap of staff in shared facilities
- Performing essential maintenance as usual wearing masks, social distancing, wearing PPE, increasing handwashing and use of hand sanitizer
- Increasing cleaning and disinfecting all surfaces in control room and all touch points in facilities and vehicles
- Avoiding planned service interruptions to customers while construction was restricted under County Order
Count on Us
Delivering
include:
- Operating and maintaining equipment to purify and clarify water;
- Monitoring and inspecting machinery, meters, gauges, and operating conditions;
- Conducting tests and inspections on water and evaluating the results;
- Maintaining optimal water chemistry;
- Applying data to formulas that determine treatment requirements, flow levels, and concentration levels;
- Documenting and reporting test results and system operations to regulatory agencies; and
- Serving our community through customer support, education, and outreach.
So the next time you turn on your faucet, think of the skilled professionals who stand behind each drop.
Substances That Could Be in Water
The sources of drinking water (both tap water and bottled water) include rivers, lakes, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases,
radioactive material, and can pick up substances resulting from the presence of animals or from human activity.
In order to ensure that tap water is safe to drink, the U.S. Environmental Protection Agency (U.S. EPA) and the State Water Resources Control Board (SWRCB or State Board) prescribe regulations that limit the amount of certain contaminants in water provided by public water systems. The U.S. Food and Drug Administration regulations and California law also establish limits for contaminants in bottled water that provide the same protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk.
Contaminants that may be present in source water include:
Microbial Contaminants, such as viruses and bacteria, that may come from sewage treatment plants, septic systems, agricultural livestock operations, and wildlife;
Inorganic Contaminants, such as salts and metals, that can be naturally occurring or can result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming;
Pesticides and Herbicides that may come from a variety of sources such as agriculture, urban stormwater runoff, and residential uses;
Organic Chemical Contaminants, including synthetic and volatile organic chemicals, which are
Radioactive Contaminants that can be naturally occurring or can be the result of oil and gas production and mining activities.
More information about contaminants and potential health effects can be obtained by calling the U.S. EPA’s Safe Drinking Water Hotline at (800)
Where Does My Water Come From?
The City of Napa’s customers are fortunate because we enjoy an abundant water supply from three sources. Depending on which water treatment plant is in operation, the source
is Barker Slough in the Sacramento Delta via the North Bay Aqueduct (treated by the Edward I. Barwick Jamieson Canyon Water Treatment Plant), Lake Hennessey (treated by the Hennessey Water Treatment Plant), or Lake Milliken (treated by the Milliken Water Treatment Plant).
Test Results
Our water is monitored for hundreds of different kinds of substances (including but not limited to metals or inorganic chemicals, volatile organic chemicals,
in 2019.
We participated in the 4th stage of the U.S. EPA’s Unregulated Contaminant Monitoring Rule (UCMR4) program by performing additional tests on our drinking water. UCMR4 sampling benefits the environment and public health by providing the EPA with data on the occurrence of contaminants suspected to be in drinking water, in order to determine if the EPA needs to introduce new regulatory standards to improve drinking water quality. Unregulated contaminant monitoring data are available to the public, so please feel free to contact us if you are interested in obtaining that information. If you would like more information on the U.S. EPA’s Unregulated Contaminant Monitoring Rule, please call the Safe Drinking Water Hotline at (800)
REGULATED SUBSTANCES
|
|
PHG |
AMOUNT |
|
SUBSTANCE |
MCL |
(MCLG) |
DETECTED |
RANGE |
(UNIT OF MEASURE) |
[MRDL] |
[MRDLG] |
(LRAA) [RAA] |
IN |
COMPLIANCE TYPICAL SOURCE |
Bromate (ppb) |
10 |
0.1 |
Chlorine (ppm) |
[4.0 (as Cl2)] |
[4.0 (as Cl2)] |
Control of DBP precursors [TOC] |
TT |
NA |
(removal ratio) |
|
|
Haloacetic Acids (ppb) |
60 |
NA |
Total Coliform Bacteria [federal Revised |
TT |
NA |
Total Coliform Rule] (Positive samples) |
|
|
TTHMs [Total Trihalomethanes] (ppb) |
80 |
NA |
|
|
|
Filter Performance
[ND]
[0.80]
2.04
(35.1)
3
(71.1)
NA
Yes |
|
Yes |
Drinking water disinfectant added for treatment |
Yes |
Various natural and |
Yes |
|
Yes |
Naturally present in the environment |
Yes |
|
|
|
SUBSTANCE |
|
|
(UNIT OF MEASURE) |
|
MCL |
Turbidity (NTU, highest detected measurement) |
|
TT = 1.0 |
|
||
Turbidity (lowest % of samples <0.3) |
|
TT = Minimum 95% of samples each month <0.3) |
Tap Water Samples Collected for Copper and Lead Analyses from Sample Sites throughout the Community in 2018
|
AMOUNT |
IN |
|
|
PHG |
DETECTED |
COMPLIANCE |
|
TYPICAL SOURCE |
NA |
|
Yes |
|
Soil runoff |
0.28 |
|
|||
NA |
100.0 |
Yes |
|
Soil runoff |
SUBSTANCE
(UNIT OF MEASURE)
Copper (ppm)
Lead (ppb)
AL
1.3
15
PHG
(MCLG)
0.3
0.2
AMOUNT
DETECTED
(90TH%TILE)
0.30
ND
SITES ABOVE
AL/ TOTAL
SITES
0/31
0/31
IN |
|
|
COMPLIANCE |
|
TYPICAL SOURCE |
Yes |
|
Internal corrosion of household plumbing systems; erosion of natural deposits; leaching |
|
||
|
|
from wood preservatives |
Yes |
|
Internal corrosion of household plumbing systems; erosion of natural deposits; leaching |
|
|
from wood preservatives |
SECONDARY SUBSTANCES
SUBSTANCE |
PHG |
(UNIT OF MEASURE) |
SMCL (MCLG) |
|
RANGE |
IN |
AVERAGE |
COMPLIANCE TYPICAL SOURCE |
Chloride (ppm) |
500 |
NS |
Specific Conductance (µS/cm) |
1,600 |
NS |
Sulfate (ppm) |
500 |
NS |
Total Dissolved Solids (ppm) |
1,000 |
NS |
Turbidity (NTU) |
5 |
NS |
UNREGULATED SUBSTANCES 1 |
|
|
22.1
290
49.5
300
0.14
Yes
Yes
Yes
Yes
Yes
Runoff/leaching from natural deposits; seawater influence Substances that form ions when in water; seawater influence Runoff/leaching from natural deposits; industrial wastes Runoff/leaching from natural deposits
Soil runoff
SUBSTANCE |
AMOUNT |
(UNIT OF MEASURE) |
DETECTED |
Hardness, Total [as CaCO3] (ppm) |
|
96 |
|
Sodium (ppm) |
19 |
|
|
RANGE
TYPICAL SOURCE
Naturally occurring in ground- and surface water Naturally occurring in ground- and source water
- Unregulated contaminant monitoring helps U.S. EPA and the State Water Resources Control Board determine where certain contaminants occur and whether the contaminants need to be regulated.
Definitions
90th %ile: The levels reported for lead and copper represent the 90th percentile of the total number of sites tested. The 90th percentile is equal to or greater than 90% of our lead and copper detections.
AL (Regulatory Action Level): The concentration of a contaminant that, if exceeded, triggers treatment or other requirements that a water system must follow.
µS/cm (microsiemens per centimeter): A unit expressing the amount of electrical conductivity of a solution.
DBP: Disinfection By Product
LRAA (Locational Running Annual Average): The average of sample analytical results for samples taken at a particular monitoring location during theprevious four calendar quarters. Amount Detected values for TTHMs and HAAs are reported as the highest LRAAs.
MCL (Maximum Contaminant Level): The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs (or MCLGs) as is economically and technologically feasible. Secondary MCLs (SMCLs) are set to protect the odor, taste, and appearance of drinking water.
MCLG (Maximum Contaminant Level Goal): The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the U.S. EPA.
MRDL (Maximum Residual Disinfectant Level): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.
MRDLG (Maximum Residual Disinfectant Level Goal): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits
of the use of disinfectants to control microbial contaminants.
NA: Not applicable
NS: No standard
NTU (Nephelometric Turbidity Units): Measurement of the clarity, or turbidity, of water. Turbidity in excess of 5 NTU is just noticeable to the average person.
PDWS (Primary Drinking Water Standard): MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.
PHG (Public Health Goal): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California EPA.
ppb (parts per billion): One part substance per billion parts water (or micrograms per liter).
ppm (parts per million): One part substance per million parts water (or milligrams per liter).
removal ratio: A ratio between the percentage of a substance actually removed to the percentage of the substance required to be removed.
TOC: Total Organic Carbon
- (Treatment Technique): A required process intended to reduce the level of a contaminant in drinking water.
Contaminants
City of Napa
EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the California State Water Resources Control Board, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the U.S. EPA (January 2019 - March 2019), tap water provided by this water utility was in compliance with federal health-based drinking water standards.
Utility details
- Serves: 172102
- Data available: 2012-2017
- Data Source: Surface water
- Total: 23
Contaminants That Exceed Guidelines
- Bromate
- Bromodichloromethane
- Chloroform
- Dibromochloromethane
- Dichloroacetic acid
- Radon
- Total trihalomethanes (TTHMs)
- Trichloroacetic acid
Other Detected Contaminants
- Bromide
- Bromochloroacetic acid
- Bromoform
- Chlorate
- Chlorite
- Chromium (hexavalent)
- Dibromoacetic acid
- Haloacetic acids (HAA5)
- Manganese
- Molybdenum
- Monochloroacetic acid
- Nitrate
- Strontium
- Strontium-90
- Vanadium
Reminder
Always take extra precautions, the water may be safe to drink when it leaves the sewage treatment plant but it may pick up pollutants during its way to your tap. We advise that you ask locals or hotel staff about the water quality. Also, note that different cities have different water mineral contents.
Sources and Resources
Sources Cited
Additional Resources
The City of Napa is dedicated to preserving the land encircling the local water source to maintain the quality and purity of the water used for Napa’s drinking water users. In the long term, preserving our watersheds is one of the least expensive and most significant actions they can take to decrease the risk of undesired constituents in their drinking water. Algal growth caused by nutrients is the number one reason for taste and odor affecting your tap water. Nutrients in the watershed are raised artificially by wastewater systems and fertilizers and runoff from agricultural traditions. Every five years, the City of Napa administers Source Water Assessments to assess the quality of the water used as the drinking water supply and monitor activities associated with the particular waterway and surrounding districts to define their contribution to contamination.
Where Does Enterprise Tap Water Come From?
City of Napa consumers benefits from a flexible water supply, including three different sources. Depending on which treatment plant is in operation, the source comes from:
- Barker Slough in the Sacramento Delta via the North Bay Aqueduct. Recreational use, urban and agricultural runoff, grazing animals, herbicide application, and seawater intrusion.
- Lake Hennessey completed April 2018: Pacific Union College Wastewater Treatment Plant, vineyards, fires, invasive species, possibly hazardous material spills due to traffic accidents (on Highway 128 near the lake), septic tank systems (in Angwin), and grazing wild animals.
- Lake Milliken completed April 2018: Fires, vineyards, and grazing and wild animals.