Skip to main content

Nitrate Notification Page (June 2023)

06/16/2023 Update

This is the most up-to-date information.

As of yesterday, June 15, 2023, the nitrate notification has been lifted by the State Water Resources Control Board. We are currently printing and preparing notices that will be distributed beginning on Monday, June 19. The water is safe for all customers and meets all of the health requirements set by the State of California.

We apologize for any inconvenience this may have caused and appreciate your patience while we resolved the situation.

Please read or download the notice below.


Notice - Nitrate Problem Corrected 06-16-23.pdf



Este informe contiene información muy importante sobre su agua potable.

Tradúzcalo o hable con alguien que lo entienda bien.


Hilmar County Water District customers were notified on June 9, 2023, of a problem with their drinking water due to high nitrate concentrations. They were advised not to give the water to infants under 6 months old or pregnant women or use it to make formula. We are pleased to report that the problem has been corrected and that it is no longer necessary to not give the water to infants under 6 months old or pregnant women or use it to make formula. We apologize for any inconvenience and thank you for your patience.

Additional information: Water sample results received between June 13, 2023, and June 15, 2023, showed nitrate levels between 1.4 milligrams per liter (mg/L) and 7 mg/L. These levels are below the nitrate standard, or maximum contaminant level (MCL), of 10 mg/L. Hilmar County Water District will continue monitoring the water produced and notify its customers of any changes to water quality. 

As always, you may contact Curtis Jorritsma at (209) 632-3522 with any comments or questions.

Please share this information with all the other people who drink this water, especially those who may have yet to receive this notice directly (for example, people in apartments, nursing homes, schools, and businesses). You can do this by posting this public notice in a public place or distributing copies by hand or mail.

This notice is being sent to you by Hilmar County Water District 

State Water System ID Number: 2410012



06/13/2023 Update

Following the cycle testing at Well 7 last week, we are providing the SWRCB with some additional sampling this week. We are hopeful that with positive results, we will be able to lift the nitrate notice very soon. 

At this point, we have not had a sample over the MCL beyond the point of entry into town, located near Camden and American.


06/09/2023 Update

Cycle sampling from Well 7, a series of eight tests within 30 minutes of well startup, all came back below the 10ppm MCL. While this is a good sign, we are still under the notice  issued by the SWRCB until they direct us otherwise.


06/09/2023 Update

Frequently Asked Questions

This Frequently Asked Questions sheet is designed to provide additional information regarding our current nitrate situation. One of the main goals of Hilmar County Water District is to provide safe, clean, and reliable drinking water. Any exception to that is an opportunity to learn, educate, and improve. We will continue to update the website with the most up-to-date information available.


What are nitrates, and where does it come from?

Nitrates are a naturally occurring nitrogen oxide found at a relatively low concentration in soil and water. It’s a necessary component of living things and essential for plant growth. That is why nitrates are widely used in agriculture as a fertilizer to enhance the growth of plants. As a result, during certain weather conditions (heavy rains and snow), the fertilizer can run off into streams and rivers or percolate down into groundwater. 

In California, nitrates are one of the most common groundwater contaminants. While 98 percent of the state’s community water systems meet all primary drinking water standards, some public wells (ongoing or intermittent) exceed the state’s nitrate standards. Wells, with nitrates regularly above the MCL, must be treated or blended with higher-quality water.

Hilmar County Water District is 100% reliant on groundwater wells to provide our water supply. These wells are located approximately two miles northeast of town and are surrounded by agricultural lands. The location of the wells, combined with the recent heavy rains, could be what caused the nitrate increase we’ve experienced.


Has the nitrate level ever been above the MCL before?

No. HCWD has never had nitrates over the MCL.


Could this have been prevented?

No. Nitrates occur naturally and can happen within agricultural applications; these are beyond the District’s control. There is no way to pinpoint how these nitrates move once they enter the soil, much less how they interact with a well pulling from three hundred feet below ground. The State of California requires HCWD to sample for nitrates and many other contaminants regularly. 


How was our elevated level of nitrates discovered?

Routine testing. Our Operations team performs regular sampling of our water supply and distribution system. The frequency of sampling depends on the contaminant itself, as well as previously recorded results. Our wells are typically sampled annually for nitrates.


Where did the elevated level of nitrates occur in the system? Is it above the limits everywhere in our water system?

Nitrate levels were initially discovered in Well 7, over two miles from our first customer. Follow-up testing provided one sample slightly above the limit (10.9 ppm) at a sample point approximately one mile from town. Additional follow-up sampling throughout the town and our water distribution system have all been below the MCL.


Who is at risk when nitrate levels are above the Maximum Contaminant Limit?

Infants under six months of age are most susceptible to nitrates/nitrites. During the early stages of development, nitrate in the body transforms into nitrite, which reacts with hemoglobin (the oxygen carrier in the blood) and prevents oxygen transport. This results in a decreased oxygen supply to the body, termed methemoglobinemia (more often called “blue baby syndrome”). It gets this name because the skin often turns blue or grayish, especially around the mouth. If these symptoms are noticed, seek medical attention immediately. Adults are at low risk of this syndrome. Adults with chronic health problems, such as heart or lung disease or enzyme deficiencies, may be at higher risk from elevated nitrate/nitrite levels. Pregnant and nursing mothers should also avoid drinking water high in nitrates/nitrites because of the potential effects passed on to the fetus or infant.


Besides drinking, is my water safe to use? 

Yes. Your water can still be used for showering, bathing, washing dishes, cleaning clothes, and more. As mentioned earlier, we have not seen nitrates above the limit in town, leading us to believe the risk from these activities is minimal.


What is HCWD doing to prevent this from happening again?

First and foremost, we will increase our monitoring efforts by conducting more nitrate samples well above what is typically required. We also can blend the water from Well 7 (where the elevated levels were discovered) with another on-system well, Well 6. We will adjust those blending levels to reduce the nitrate level and remain under the MCL. Longer-range plans include the construction of a 1-million-gallon storage tank to blend better and allow for treatment as needed.


Should you have any other questions, please call the Hilmar County Water District Office at (209) 632-3522.


06/08/2023 Update

All water customers of Hilmar County Water District will receive a door hanger notice regarding our water distribution system and current nitrate levels. The same notice is available for download and displayed below.

This notice was prepared in cooperation with the State Water Resources Control Board for the Hilmar County Water District.

We will continue to post updates on this page so that our customers can remain informed with accurate information.

We apologize for the inconvenience and look forward to resolving this matter quickly.


-Hilmar County Water District

Notice - Nitrate Levels June 2023.pdfNotice - Nitrate Levels June 2023 SPANISH.pdf




Hilmar County Water District water has high levels of nitrate.


Water sample results received from Well 7 between May 18, 2023 and June 6, 2023 showed nitrate levels between 12.5 milligrams per liter (mg/L) and 19.4 mg/L. Water sample results from Well 6 between May 18, 2023, and June 6, 2023 showed nitrate levels between 7.5 mg/L and 8.4 mg/L. Wells 6 and 7 are blended prior to being served to the customers of the Hilmar County Water District water system. Water sample results from the blended point on June 2, 2023, and June 7, 2023 showed nitrate levels of 6.3 mg/L and 10.9 mg/L.  This is above the nitrate standard, or maximum contaminant level (MCL), of 10 mg/L. Nitrate in drinking water is a serious health concern for infants less than six months old.

What should I do?

  •  DO NOT GIVE THE WATER TO INFANTS.  Infants below the age of six months who drink water containing nitrate in excess of the MCL may quickly become seriously ill and, if untreated, may die because high nitrate levels can interfere with the capacity of the infant’s blood to carry oxygen.  Symptoms include shortness of breath and blueness of the skin.  Symptoms in infants can develop rapidly, with health deteriorating over a period of days.  If symptoms occur, seek medical attention immediately.
  • PREGNANT WOMEN SHOULD NOT CONSUME THE WATER. High nitrate levels may also affect the oxygen-carrying ability of the blood of pregnant women. Water, juice, and formula for children under six months of age should not be prepared with tap water.  Bottled water or other water low in nitrates should be used for infants until further notice.
  • DO NOT BOIL THE WATER.  Boiling, freezing, filtering, or letting water stand does not reduce the nitrate level.  Excessive boiling can make the nitrates more concentrated, because nitrates remain behind when the water evaporates.

 If you have other health issues concerning the consumption of this water, you may wish to consult your doctor.

What happened?  What is being done?

Nitrate in drinking water can come from natural, industrial, or agricultural sources (including septic systems, storm water run-off, and fertilizers).  Levels of nitrate in drinking water can vary throughout the year. We will let you know if the amount of nitrate is again below the limit.

Water from Well 6 and Well 7 is blended prior to being served to the Hilmar County Water District water system. Recently, the blended point showed sample results over the MCL. The Hilmar County Water District is conducting cycle testing of Well 7 to determine compliance solutions. In addition, the Hilmar County Water District is in preliminary phases of constructing a tank to blend and monitor nitrate and arsenic levels for treatment and compliance.  

For more information, please contact Curtis Jorritsma, General Manager at 209-632-3522 or P.O. Box 1060, Hilmar, CA 95324.

Additional contact information: State Water Resources Control Board, Merced District Engineer, (559) 447-3316. 

Please share this information with all the other people who drink this water, especially those who may not have received this notice directly (for example, people in apartments, nursing homes, schools, and businesses).  You can do this by posting this public notice in a public place or distributing copies by hand or mail.

Secondary Notification Requirements

Upon receipt of notification from a person operating a public water system, the following notification must be given within 10 days [Health and Safety Code Section 116450(g)]:

·      SCHOOLS: Must notify school employees, students, and parents (if the students are minors).

·      RESIDENTIAL RENTAL PROPERTY OWNERS OR MANAGERS (including nursing homes and care facilities):  Must notify tenants.

·      BUSINESS PROPERTY OWNERS, MANAGERS, OR OPERATORS:  Must notify employees of businesses located on the property.

This notice is being sent to you by Hilmar County Water District.

State Water System ID#: 2410012                                                                                                           

Date distributed: June 8, 2023