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Nitrate Notification Page (December 2023/January 2024)


HCWD has spent the last few weeks investigating this issue and is in close communication with the State Water Resources Control Board (SWRCB). Unfortunately, at this point, the SWRCB is not yet willing to let us rescind the Nitrate notice. Because of that, all customers will receive an updated notice with their monthly statement, which includes new information (discussed below) from the last few weeks. 

While we had hoped to be lifting the notice with this update, the safety of our customers is paramount. This notice will remain in effect until we are confident that the water we supply is below the nitrate limits and meets all health and safety standards. We appreciate the SWRCB's coordination and our customers' patience, and we are confident this issue will be resolved soon.

Continue to check back here for the most current and accurate information.

Read below for a more detailed explanation of our system and the current situation.

Here's a more in-depth explanation of where our water comes from to provide our customers with the most complete information. Currently, the District receives water from two wells (Jake Well#6 and Woody Well #7) approximately two miles north of town. These two wells pump into a single transmission main that provides water to our customers. The blend location, referred to as the TID Yard sample point, is located on the transmission main, very close to the middle of that two miles: almost exactly one mile from the source wells and one mile before our distribution system (the network of pipes providing water to our customers).

In the last update, we let you know that we'd be pulling samples from all three locations, and the results are as follows:

Well 6 (mg/L)Well 7 (mg/L) TID Yard (Blend Point)
 01/04/2024 9.896.769.31

Well 7 was below Maximum Contaminant Limit (MCL) in every sample. Well 7 also produced approximately 92% of the District's water during this time. That is favorable data. Well 6 had two samples that exceeded the 10 mg/L MCL limit but then dropped back below it. The results from both wells show that our source water is mainly free of elevated nitrate levels.

The blend location is different. Those results remain above the MCL. We continue to investigate this sample location to understand why there is such a sharp increase in Nitrate levels. From a simple mathematical perspective, it's hard to comprehend how water below the limit from two wells can come together in one transmission main and then register Nitrate levels double that of the source. In addition to continuing the current sampling schedule, this is where we are directing most of our focus.

As mentioned, we are working closely with the SWRCB to resolve this situation. Please be sure to read the updated notice included in your monthly statement or access it below.

For more information, please get in touch with the District Office at 209-632-3522.

Thanks again for your understanding.


Hilmar County Water District


Lab results from January 4th were all below the limit of 10 ppm and within compliance with the Department of Drinking Water's (DDW) standards, which is good news.

A follow-up meeting with the Department of Drinking Water on Friday was also very productive. While they were pleased with the most recent lab results, they would like HCWD to do additional sampling over the next two weeks to build a data set for evaluation. The District will pull samples on January 9th, 11th, 16th, and 18th. The following week, we will meet with DDW to review those results. At that time, we will decide as to how to proceed.

Hilmar County Water District will provide updates here as they become available.

Nitrates most commonly affect infants (younger than six months), pregnant or nursing women, and people who currently or previously have had respiratory issues. For all others, the nitrate risk of the current situation is extremely low.

For more information, please contact the District Office at 209-632-3522.

Thanks again for your understanding.


Hilmar County Water District


Lab results from January 2nd (Tuesday) remained slightly above the limit. However, results from our samples taken one day later, on January 3rd (Wednesday), were all below the limit of 10 ppm (including the source we believed was causing the issue). These results have been presented to the State Water Resources Control Board - Department of Drinking Water, and they have asked HCWD to collect additional data before making any further determinations. Collection of this data will take place over the next several days. We will update this page accordingly as those results become available.

As the notice distributed stated, nitrates most commonly affect infants (younger than six months), pregnant or nursing women, and people who currently or previously have had respiratory issues. The risk from nitrate exposure at these levels remains relatively low for all others.  

For more information, please get in touch with our District Office at 209-632-3522.

Your ongoing patience is appreciated as we continue to explore this situation.


Hilmar County Water District


We continue to monitor the water supply for Nitrates and are currently awaiting updated sample results from our laboratory. Once we have that information, we will report any relevant news.

As a District that relies solely on groundwater wells for its water supply, it's incredibly challenging to pinpoint why these situations arise. We are evaluating one of our system wells, which might have caused the high uptick in nitrate results. However, this task is quite challenging, knowing that we are pumping water from several hundred feet below ground without any way of really seeing or knowing what's happening down there.

For more information, please get in touch with our District Office at 209-632-3522.

We understand this is an inconvenience to our customers, and we appreciate your patience as we work through it.


Hilmar County Water District.

12/30/2023 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 as soon as we are able to.


-Hilmar County Water District

Notice - Nitrate Notice December 2023.pdfNotice - Nitrate Notice December 2023 SPANISH.pdfNitrate Fact Sheet and Frequently Asked Questions (Updated 12:2023).pdf




Hilmar County Water District water has high levels of nitrate.


The following water sample results were received between December 19, 2023 and December 29, 2023:

Well #6: Levels between 10.4 milligrams per liter (mg/L) and 12.1 mg/L. 
Well #7: Levels between 6.8 mg/L and 12.3 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 a blended location on for the dates mentioned above were:

Blend Sample Point (near TID Yard):  Levels between 10.2 mg/L and 14 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 and even sometimes, day to day as Hilmar County Water District has observed. 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 our sources to determine compliance solutions. In addition, the Hilmar County Water District is working on projects that will help us 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. 

Copies of this notice are being distributed by hand. 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). 

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