Well Water Filters & Nitrate Levels

Nitrate Risks

• According to the Vermont Department of Health, water with nitrate levels above 10 mg per liter is unsafe and should be treated before being used for drinking or cooking. Use bottled or alternative sources of water until the water is corrected. If levels are above 5 mg, look for a source of contaminants and try to reduce them if possible. Nitrates are a form of nitrogen found naturally in the environment, but at high levels they can be unhealthy. Septic tanks, agricultural fertilizers and compost are common sources of nitrate contamination.

Reverse Osmosis

• This process greatly reduces, but does not completely remove nitrates from well water. It involves a filter or membrane that can be installed under a sink or on a counter. Water is forced through with pressure so that minerals and nitrates are filtered out. Much of your water will remain behind as waste water but this waste can be reduced by increasing the amount of pressure in the system. Such systems require a lot of energy and may not yield enough treated water to support livestock.

Ion Exchange

• Ion exchange systems use a tank filled with beads that are charged with chloride or other substances and can treat large amounts of water. As nitrates pass through, they are exchanged for the chloride particles. The drawback of ion exchange is that it works less efficiently for water containing lots of sulfites, which also try to exchange with the chloride. Since it can make water more corrosive, a neutralizing system may also be necessary for treating the water afterward. A salt tank supplies the chlorides must be refilled occasionally.

Other Options

• There are a few simple and cost-efficient methods for reducing nitrates, but they may require some diligence. One of the oldest types of water purification processes -- distillation -- will effectively remove nitrates and other minerals dissolved in water. In this process, water is boiled and the steam is collected. Nitrates and other contaminants are left behind in the boiling tank. Another way of effectively reducing nitrates is to simply mix low-nitrate water in with your well water to reduce the concentration to a safe level.