A. Nitrate is a naturally occurring chemical compound that is formed in the soil when nitrogen and oxygen combine. Small amounts of nitrate are normal but large amounts can pollute groundwater and cause severe consequences to life.
Q. What are health problems associated with nitrate?
A. When nitrates enter the body, stomach bacteria converts nitrate to nitrite. Adults have low pH (high acidity) stomach acid that destroys this nitrite producing bacteria. Infants, however (especially those less than three months in age), do not have developed digestive systems that can destroy the stomach bacteria, so infants can develop excess amounts of nitrite in their bodies and develop methemoglobinemia. Methemoglobin is a converted form of hemoglobin, which is found in red blood cells and normally carries oxygen in the body’s bloodstream. In methemoglobin form, these cells are unable to transport oxygen and these infants now become oxygen starved. Livestock are also susceptible to nitrate poisoning.
Q. Where do nitrates come from? What are the sources of nitrate in my well water?
A. Sources of nitrate in the soil are chemical fertilizers, septic system discharge and livestock waste. A portion of chemical fertilizer will convert to nitrate in the soil. Ammonia is present in the waste of both humans and animals. It enters the soil from inadequate or poorly managed septic systems. Plants can only absorb a certain level of nitrate from the soil. The excess is then carried down through the soil into the groundwater by the action of rain, snowmelt and irrigation.
Q. How often should I test for nitrate in my well water?
A. The United States Environmental Protection Agency (EPA) recommends that well users test their water everyone to three years for total nitrate and biological content. If the taste, odor, or appearance changes, the water should be tested more frequently.
Q. What is the maximum contaminant level of nitrate recommended?
A. Nitrate is either expressed in reports as Nitrate-N (nitrate as nitrogen) or Nitrate as Nitrate. The maximum contaminant level (MCL) for nitrate-N is 10 PPM (also known as milligrams per liter). To express nitrate as nitrate, multiply by 4.4: for example, the MCL for nitrate as nitrate is 44 PPM.
Q. How can I reduce the risk of nitrate contamination in my well water?
A. EPA recommends homeowners follow these guidelines to reduce the risk of nitrate contamination:
1. Reduce your use of fertilizer: use commercial fertilizers only when necessary, and always according to the manufacturer’s recommendations. Never over-fertilize.
2. Proper well construction: A well should always be located up-gradient or in reverse direction of groundwater flow direction from your septic system. There should be a minimum of 100 feet separating your well from your septic tank and leach field, whichever is the closer (contact your county health department as their requirements could be greater). Your wellhead casing should extend above the ground and be protected within an earthen berm (a conical mound) to divert surface drainage away from the wellhead. Make sure that the well casing has at least a 50 foot deep annular seal of cement (grouting around the well casing) and a concrete slab covering the wellhead.
3. Operate and maintain your septic system correctly: Proper maintenance and operation of your septic system is critical in saving money and avoiding system failure, which will ultimately lead to groundwater contamination and the possibility of health-related issues.
Q. How can I remove nitrate for my home well water system?
A. The most commonly used treatment approach is ion-exchange, the same technology water softeners employ. With this type of system, chlorides are exchanged for the nitrate, and the high nitrate waste is flushed into a holding tank or drain field. Similar to a water softener, salt is added to a salt tank, and the nitrate resin is regenerated automatically with saltwater. If you are on your own private well you can choose to either remove the nitrate throughout the house or purify at one or more faucets.
Q. Is pretreatment before the nitrate system needed?
A. Pretreatment and total system design is important. If you are looking for a nitrate filtration system for your small community water system, each system installed must be certified by the Health Dept. for nitrate removal. Typically, all the water must be filtered, and individual point-of-use filters at kitchen taps are not allowed for compliance with the nitrate MCL standard.
Nitrate systems remove both nitrate and sulfate, so it is important to know both the nitrate and sulfate levels.
Q.What pretreatment should I consider?
A.We recommend Iron levels less than 0.3 PPM; Manganese less than .05 PPM; Hydrogen sulfide 0.00 PPM; Hardness less than 100 mg/L or about 6 grains per gallon.
Q.I have hard water, and I also have nitrate. Can’t I just mix the nitrate resin with softening resin to have just one combination system?
A. You can try but generally we don’t recommend this. The nitrate resin has different salting requirements than a water softener, and it is too easy to exhaust either the softening resin or the nitrate resin and it makes it difficult to troubleshoot later if you see nitrate or hardness leakage.
Q.How long does the nitrate resin last?
A. As long as it regenerates regularly with salt it should last for 5 to 7 years.