Lower Yakima Valley Groundwater
- Information for community members on residential or private wells
- Health information about nitrate
- About EPA and DOJ's legal action
- Background
Information for community members on residential or private wells
Call EPA at 206-676-4250 if you have specific questions not addressed on this page.
To join our mailing list, send an email to epa-seattle@epa.gov with "Lower Yakima Valley Groundwater Mailing List" in the subject line.
Fact sheets are available below in printable format (PDF) in both English and Spanish:
- EPA urges well testing for nitrate, files legal action (pdf)
- La EPA recomienda hacer pruebas de detección de nitrato en los pozos e inicia acciones legales contaminada con nitrato (pdf)
Is my well affected?
If you obtain water from a residential or private drinking water well within the "area of concern" in EPA and DOJ’s legal action, your drinking water may be contaminated with high levels of nitrate.
Look up your address
Use our address look-up tool to determine if your home is within the area of concern in EPA and DOJ’s legal action.
Types of wells impacted
Residential or private wells are most at risk of nitrate contamination. These include:
- Individual drinking water wells that serve one single home.
- Shared drinking water wells that serve two homes.
- "Group B" public water systems: drinking water wells that provide drinking water to fewer than 15 service connections and fewer than 25 people per day.
"Group A" public water systems are regulated by the Safe Drinking Water Act and are not affected by this legal action. Homes receiving water from a Group A system are not at risk from this nitrate contamination in private and residential wells. One way to know whether you obtain your drinking water from a Group A or Group B public water system is to check your water bill and contact your public water system for more information.
How can I get my well tested?
If your well is located in EPA and DOJ's area of concern, call EPA at 206-676-4250 to learn how to access free drinking water well testing.
On December 17, 2024, the U.S. District Court ordered the dairies to immediately test residential drinking water wells in the area of concern for nitrate and provide alternative water to community members where test results exceed 10 milligrams/liter (mg/L). To comply with the court’s order, the dairies must submit a plan for testing residential drinking water wells within 30 days and complete the testing within 60 days of EPA’s approval of the plan.
What if my well is located outside of EPA's area of concern?
Nitrate contamination is a concern throughout the Lower Yakima Valley. EPA is working with Washington state and local agencies as they develop a strategy to address high nitrate levels in groundwater throughout the Lower Yakima Valley. This strategy includes the Lower Yakima Valley Groundwater Management Area Safe Drinking Water Initiative to offer free drinking water well testing for homes located in the Lower Yakima Valley Groundwater Management Area, and water for homes with nitrate in drinking water above EPA’s health-based safety standard of 10 mg/L.
If you are located in Yakima County but outside of EPA’s area of concern, please visit Lower Yakima Valley Groundwater Management Area Safe Drinking Water Initiative or call 866-886-7117 for more information.
If you prefer to schedule and pay for a drinking water test yourself, there are several certified laboratories in Yakima County. Visit Yakima County Health District Drinking Water Testing.
Health information about nitrate
Too much nitrate in your body makes it harder for red blood cells to carry oxygen, and symptoms can appear within hours or days. A single exposure to high nitrate levels can cause health effects in babies, pregnant people and sensitive adult populations with certain health conditions.
Infants exposed to high amounts of nitrate may develop a rare but potentially deadly illness called "blue baby syndrome," or methemoglobinemia.
Symptoms include shortness of breath and blueness of the skin. For people with dark skin, look for a bluish color on fingernails and toenails, lips, and inside the nose and mouth.
What is nitrate?
Nitrate is a compound of nitrogen and oxygen atoms and is naturally found in air, soil, water and some foods. In industry, nitrate is used as fertilizers for crops and lawns. Additionally, nitrates are used in food preservation, certain pharmaceutical medications, as well as the manufacture of munitions and explosives. EPA’s maximum contaminant level (MCL) for nitrate is set to protect against blue-baby syndrome. The MCL is 10 milligrams per liter (mg/L) of nitrate measured as nitrogen. Consuming nitrate in levels above the MCL may cause adverse health impacts.
- Learn more about nitrate from the Agency for Toxic Substances and Disease Registry.
Why is nitrate contamination a concern?
Nitrate is an acute contaminant, meaning that health effects can occur immediately (i.e., within hours or days) after short-term exposure. Too much nitrate in your body makes it harder for red blood cells to carry oxygen. While most people recover quickly, this can be very dangerous for infants and some adults. Particularly vulnerable populations may include infants under the age of 6 months, people who are pregnant, and those with specific health concerns. Infants exposed to high amounts of nitrate may develop a condition called methemoglobinemia, commonly known as “blue baby syndrome.” This illness is rare, but it can be fatal. Infants are especially vulnerable if they are fed with formula mixed with well water that has a high nitrate concentration.
What are the possible health effects of nitrate exposure?
Short-term: Excessive levels of nitrate in drinking water can cause serious illness and sometimes death. The serious illness in infants is due to the conversion of nitrate to nitrite by the body, which can interfere with the oxygen-carrying capacity of the child’s blood leading to blue baby syndrome (methemoglobinemia). This can be an acute condition in which health deteriorates rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin.
How are people potentially exposed to nitrate in their drinking water?
People in the Lower Yakima Valley are most commonly exposed to concentrations of nitrate in their drinking water if they have a private or residential well that becomes contaminated from nitrate sources such as concentrated animal feeding operations and irrigated crop fields.
What should I do if my water has elevated nitrate?
EPA’s health-based safety standard - or “maximum contaminant level” often referred to as MCL - for nitrate is 10 milligrams per liter (mg/L). If nitrate in your drinking water exceeds 10 mg/L, you should find an alternative drinking water supply. The quickest thing to do is to begin using bottled water for drinking, cooking, preparing baby formula, for washing fruits and vegetables, washing baby bottles and pacifiers, and for brushing your teeth.
Another option is to install treatment that will remove nitrate from your water such as reverse osmosis filter.
Is it safe to shower or bathe in water if it is over the nitrate maximum contaminant level of 10 mg/L?
Nitrate is only a concern for ingestion (eating and drinking). It is not easily absorbed through intact skin. Showering and bathing in water with high nitrate is generally considered safe. However, you should be careful not to consume water with high nitrate while showering, bathing, or brushing your teeth, and you should be especially careful when bathing babies.
People who install reverse osmosis filters for nitrate often install them just for their kitchen sink faucet, and they use that faucet for their cooking and drinking water.
I use a carbon filter. Will this help?
No. Activated carbon filters – such as those in a “Brita” water pitcher – do not remove nitrate.
Will boiling my water help?
No. Boiling water will not reduce nitrate levels. Boiling water will make the level of nitrate worse because some of the water will evaporate but the nitrate will not. This increases the concentration of nitrate in water.
How do I protect my water from nitrate exposure?
Private and residential well owners and users
If your well is located in the Lower Yakima Valley, it is at risk of nitrate contamination.
- Test your well routinely. EPA recommends that community members test their private well for nitrate and bacteria at least once a year.
- If nitrate levels exceed the maximum contaminant level, immediately use alternative water.
- Ensure your well is up to code with state regulations.
- If you have a well-house, do not store fertilizer (or other chemicals) in it.
Those serviced by public water systems
Under the Safe Drinking Water Act, a “public water system” is one that serves 15 or more service connections, or 25 or more people. Washington “Group A Public Water Systems” are public water systems under the Safe Drinking Water Act.
- If nitrate levels are found to be consistently above the maximum contaminant level at a public water system, your water supplier must take steps to reduce the amount of nitrate so that they are consistently below that level.
- The system must notify the public via newspapers, radio, TV and other means. More actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.
- This information can be obtained through your Consumer Confidence Report (CCR). Public water suppliers mail this report to customers every year and they are available by request. If you did not receive your CCR, contact your public water supplier to request a copy. The CCR includes information on nitrate.
About EPA and DOJ's legal action
On June 26, 2024, the U.S. Department of Justice (DOJ) filed a legal action on behalf of EPA against three nearby dairies identifying them as a source of nitrate that is contaminating nearby drinking water wells and seeking to require that the dairies take actions to protect nearby community members.
On December 17, 2024, the U.S. District Court ordered the dairies to immediately:
- Test down-gradient wells and supply alternative drinking water (reverse osmosis filter or bottled water) to homes where nitrate in well water exceeds 10 milligrams per liter, the health-based safety standard.
- Provide professional maintenance service for any impacted home with a reverse osmosis filter.
- Immediately test a lined lagoon for leaks.
- Continue testing from a network of groundwater monitoring wells to measure nitrate coming from the dairies’ operations.
To comply with the court’s order, the dairies must submit a plan for testing residential drinking water wells within 30 days and complete the testing within 60 days of EPA’s approval of the plan. The order from the court requires the dairies to provide alternative water to homes where nitrate levels are above 10 mg/L.
In its lawsuit, EPA also alleges that the dairies failed to comply with a 2013 consent order with EPA and continued to discharge nitrate into groundwater at levels that present a risk to down-gradient community members.
- Order Granting Motion for Preliminary Injunction, U.S. vs Cow Palace LLC, et al. (pdf)
- Complaint, U.S. vs. Cow Palace LLC, et al. (pdf)
- Motion for Preliminary Injunction, U.S. vs Cow Palace LLC, et al. (pdf)
- Declaration of G. Schnaar in Support of U.S. Motion for Preliminary Injunction (pdf)
- Declaration of Dr. C. Teaf in Support of U.S. Motion for Preliminary Injunction (pdf)
- Declaration of E. Winiecki in Support of U.S. Motion for Preliminary Injunction (pdf)
- Read EPA's press release - July 2, 2024
Background
In 2010, EPA found that nitrate contamination of wells in the Lower Yakima Valley – an area historically overburdened by environmental and public health challenges – may present an “imminent and substantial endangerment to human health.”
In March 2013, EPA and several dairies in the Lower Yakima Valley signed a legal agreement called a consent order to address sources of nitrate contamination in groundwater near and down-gradient of the dairies’ facilities. In signing the consent order, the dairies agreed to:
- Provide an alternate source of drinking water for neighbors within one mile down-gradient of the dairies whose wells have levels of nitrate above 10 mg/L, EPA’s health-based safety standard.
- Conduct soil and groundwater testing at each dairy to evaluate if nitrogen sources are being controlled.
- Take steps to control nitrogen sources (manure and commercial fertilizer) at their facilities.
In October 2021, EPA received a Safe Drinking Water Act section 1431 emergency petition regarding nitrate concentrations in groundwater throughout the Lower Yakima Valley. The citizen group petitioners claim that nitrate contamination in underground sources of drinking water (i.e., private wells) is causing an imminent and substantial endangerment to public health and request that EPA take certain actions to address the contamination.
EPA has engaged with state and local government as they develop a strategy to address high nitrate levels throughout the Lower Yakima Valley. Copies of documents related to the Citizen Petition for Emergency Action are available on EPA's document sharing site.
In November 2023, EPA released the Protocol for the Nitrate and Nitrite IRIS Assessment (Oral). This document explains how EPA will conduct an assessment of the health effects of exposure to nitrate and nitrite.