Nitrate is a regulated drinking water contaminant with an established state and federal Maximum Contaminant Level (MCL) of 10 mg/L (as N). Nitrate is the most-common chemical contaminant in the world’s groundwater aquifers. Information on health effects related to nitrate can be found in the resources listed at the bottom of this page.

Golden State Water routinely monitors and tests for more than 230 contaminants to ensure the water we deliver to customers meets all state and federal drinking water standards. Golden State Water makes water quality information available via annual Consumer Confidence Reports (CCR).

As your water provider, we continually invest in water infrastructure, treatment and testing and take great pride in providing you with high-quality, reliable water.

Frequently Asked Questions

Q:  What is Nitrate and where does it come from?
A:  Nitrate is a chemical that is produced in the atmosphere from nitrogen and occurs in groundwater at concentrations below 2 mg/L. High concentrations of nitrate in groundwater are generally associated with septic systems, confined animal feeding operations or fertilizer use. Nitrates are also present in treated wastewater and can be present in surface water. In addition, nitrate is used in industry, for example, in the production of fertilizers and explosives.

Q:  Has Nitrate been found in my drinking water?
A:  All water served is below the MCL for nitrate. Nitrate levels below the MCL have been detected in treated drinking water in 37 of our water systems. Systems with groundwater sources that have nitrate levels above the MCL have treatment in place to ensure that the drinking water provided to customers meets state and federal water quality standards. Click here to see a summary table of recent nitrate results.

Q:   How is Nitrate removed from contaminated source water?
A:  Methods to remove nitrate from contaminated source waters include distillation, reverse osmosis, ion exchange, electro-dialysis, and biochemical denitrification. Golden State Water uses ion exchange and blending to produce drinking water with nitrate levels below the MCL.

Customers with questions about nitrate, drinking water regulations or the drinking water served to their community are asked to contact Golden State Water’s 24-hour Customer Service Center at 800.999.4033 and request to speak with your local Water Quality Engineer.

Resources for Additional Information

State Water Resources Control Board

State Water Resources Control Board (Groundwater Information Sheet)