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Yakima County's Nitrate
Treatment Pilot Program

Providing water treatment systems, education and technical assistance to households with individuals at high public health risk from nitrate contaminated wells.

What is a reverse osmosis (RO) system? How does it work?

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Reverse osmosis is a high efficiency filtering treatment system. It is the most common treatment technology used by premium bottled water companies and has been used as a home water purification system as early as the 1970s. It is effective in eliminating or substantially reducing a very wide array of contaminants, and of all technologies used to treat drinking water in residential applications, it has the greatest range of contaminant removal.

Reverse Osmosis (RO) System - Where is it installed? What type of maintenance is required?

Reverse Osmosis (RO) is normally installed under a kitchen sink as shown on the figure below. 

Reverse Osmosis System

Source: North Dakota State University
A Typical Home RO System Includes: (1) particle filter, (2) reverse osmosis membrane unit, (3) pressurized treated-water storage container, (4) carbon absorption post-filter, and (5) separate treated-water tap.

I am a renter. Can I have the system installed, or will my landlord (homeowner) do it?

Renters can have a system installed only with the homeowner's permission.

What are the ongoing costs of the system? Who pays for that?

It is estimated that installation of the system will cost around $800 per unit.  Maintenance of the system, which includes periodic replacement of filter cartridges, is about $20 a month.

I can't afford any of this. What next?

Priority is given to homes with high health risks.  If there is extra funding, this will be made available to others.  Unfortunately, only limited funding is available. If you have an immediate concern about your private well, you may want to consider purchasing bottled water for drinking and cooking.

Does the system protect me from all the "bad stuff" in my water supply?

The nitrate treatment system will treat most contaminants, but not all.  The water sample will identify the contaminants present in your water.  The system installer can provide advice if there are other contaminants other than nitrate present in your water source.

What happens if I have high nitrate and don't do anything about it?

The good news is, most healthy people are not at risk from nitrate. However, please review "Why are pregnant women, infants and others at high public risk?"

If I have questions, who can I talk to?

For the Nitrate Treatment Program, contact the Yakima County Public Services Nitrate Hotline at 855-740-8429.  For health concerns or questions, contact the Yakima Health District at 800-535-5016. Or visit our website at