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Nitrates are a common contaminant in drinking water. They come from many sources and may be found at high levels in public water supplies, agricultural wells, private well systems, and rainwater catchment systems. Nitrates can make you sick if your body is unable to remove them fast enough through normal metabolism, or when they react with other substances such as ammonia, chlorine, bleach, or other chemicals.
This article will teach you how to safely remove nitrates from your drinking water supply so that they do not become a health hazard for you or your loved ones.
Where Do Nitrates in Drinking Water Come From?
It is important to know where your nitrate contamination is coming from before you start treatment because different methods of removal will work better for certain sources of nitrates.
Nitrate contamination can come from a few different sources, but the most common are:
- Agricultural runoff
- Septic tanks and cesspools
- Faulty pipes in your plumbing system or dishwasher leaks
The extent to which these contaminants affect your water will depend on whether it is surface water – rainwater that has made its way into a water supply – or groundwater.
Agricultural runoff is a major source of pollution. Nitrogen-based fertilizers are often used on crops, and livestock manure is applied to fields without being composted. Nitrates from agricultural sources have been found in groundwater, soil, surface waters, and in the air.
The use of these fertilizers is important to food production. They can create a serious health risk when nitrates enter drinking water supplies and get consumed by humans.
What is the Accepted Limit of Nitrates in Water?
The EPA has set the maximum contaminant level (MCL) for nitrates in public water systems at 10 milligrams per liter of nitrogen – the equivalent of ten parts per million. Some public water systems have exceeded this MCL, and the EPA will issue “boil-water advisories” for those communities to protect consumers from potential health risks posed by ingestion of these contaminants. The cost of treatment varies depending on which technology is employed to remove nitrates.
Health Effects of Nitrates in Drinking Water
Nitrates in drinking water can cause health problems such as:
- Blue Baby Syndrome — Drinking untreated water containing high levels of nitrates over an extended period of time may cause infants to develop a rare condition called Blue Baby Syndrome or methemoglobinemia, which is characterized by the inability to use oxygen normally (anoxia) and a bluish appearance of the skin.
- Cancer — Exposure to high levels of nitrates in water may also increase your risk for some types of cancer, such as bladder cancer or esophageal cancer.
Can Nitrates Affect Adults?
Nitrates are known to cause blue baby syndrome, but the effects on adults are still unknown. Problems like an increased heart rate, vomiting, stomach cramps, and headaches may be possible.
Pregnant mothers should avoid drinking water with high levels of nitrates. Nitrates in water increase the risk of premature births that can cause complications for the mother and the child.
There is still more research on whether the intake of nitrates in water breeds gastrointestinal cancer. The WHO acknowledges that nitrates are carcinogenic to humans. There is no evidence whether consuming water with nitrates alone can cause cancer.
How to Eliminate Nitrates in Tap Water
The simplest way to remove nitrates from tap water is to use reverse osmosis. It’s a fairly advanced process, but it will effectively eliminate the nitrate contamination from your drinking water. If you follow these steps, you should be able to remove 90-95% of nitrates in your tap water.
The first step is to screen out any debris that may be in the water. To do this, add a sediment filter and allow it to sit overnight. This will let the particles settle while smaller ones will pass through the filter.
Next, pour the water slowly through a carbon block filter. Carbon block filters will remove about 90-95% of the nitrates from your tap water.
The third step is to pass the water through an activated charcoal filter. This will remove any chemicals that were missed by the first two filters and ensure that your drinking water is purified.
The fourth step is optional and depends on how large of a volume you will be treating. If you are only trying to purify a gallon or two then you may skip it. Add a reverse osmosis unit to remove any leftover nitrates that the charcoal filter missed. These units will ensure that your water is nitrate free.
If you would like to read more about reverse osmosis water filtering, check out our guide here.
If you are only trying to purify a gallon or two of water then you may want to consider using an activated carbon filter which can be purchased online or at some farm supply stores. These filters are much quicker than the whole house reverse osmosis system, and they cost half as much.
First, pour a gallon or two of water into a bucket. Then add one activated charcoal block to the water, and let it sit for about 15 minutes. Next, dump the contents of the bucket into your garden or lawn. This is great fertilizer.
After that simply repeat steps 1- 3 until you have filtered all of your water. Now you’re done! Enjoy your fresh water – no nitrates, and it’s free from pharmaceuticals & other pollution as well.
How to Eliminate Nitrates in Water Using Filtration and Sedimentation
You can remove nitrates from your drinking water with ease using filtration and sedimentation. Filtration methods include:
- Activated alumina
- Ion exchange
- reverse osmosis
When you’re ready to buy a whole home water filtration solution, check out our guide to assist you.
Activated Alumina
Activated alumina treatment is a simple process of passing water through an inert substance that removes nitrates in the form of soluble aluminum-nitrate complexes. The activated alumina also has several other beneficial effects on drinking water, such as improving its taste and color.
Ion Exchange
Ion exchange treatment is based on a chemical reaction between nitrates and an ion-exchange resin, leading to the formation of nitrate ions which are removed from solution in favour of less harmful ions like ammonium or sodium. Ion-exchange resins work best for removing inorganic acids like nitrates, chlorides, and sulphates.
The first step in the process of removing nitrates using ion exchange is to add sodium hydroxide to the water. This will remove nitrates from the water by converting them to ammonia and sodium chloride. If this process is not successful the next step should be adding a strong base such as calcium oxide or copper sulphate to react with free acidic materials remaining in the water.
Ion exchange resins are typically used for removing nitrates and chlorides in groundwater supplies, but they can also be used as a final treatment after coagulation or activated-carbon adsorption if necessary. Ion Exchange is also used to remove lead from water.
Cationic ion-exchange resins remove both organic acids (acetic acid) and inorganic acids (nitric or sulphuric). Electrodes are also used to control pH levels, but they typically require more electricity. Electrodes can be useful for removing hard ions from water if the water is not too acidic.
Use our guide to the best water ionizers to help you make your purchase if you decide to go this route.
Reverse Osmosis
A more affordable way is through reverse osmosis treatment: this process removes 95% of all contaminants from drinking water by forcing it down through a semipermeable membrane. The membrane removes nitrates and other contaminants by trapping them within the membrane.
Filtration methods are more commonly utilized by homeowners because they allow removal of organics as well. They involve binding nitrates with activated carbon, and then removing the bound molecules through filtration.
Boiling
Nitrates in water can also be removed by boiling or aeration. These methods work rapidly, but are not as effective on a large scale. Boiling, in particular, will kill any bacteria or microbes in the water that may contribute to nitrate contamination. It should be noted that some food items can have high levels of nitrates which cannot be eliminated through this process.
After boiling, the water should be allowed to cool below 80 degrees Fahrenheit before it is used again for drinking or cooking. This will reduce any potential bacterial growth that could lead to nitrates in your food and potable water sources.
These processes should remove approximately 50% of nitrates from water. However, they require additional chemicals such as sodium hydroxide, potassium permanganate, or ozone.
Activated Carbon
Activated carbon is a good choice if you have organic acid (acetic acid) contamination. Activated carbon adsorption (a carbon filter) works by trapping the contaminants on a granular form of activated carbon. It should be noted that this process can remove a variety of chemicals and pollutants including nitrates.
Nitrate-Reducing Bacteria
Another way to lower the nitrate level in water is by using a nitrate-reducing bacteria. The process is expensive, but it can be done quite easily at home. Nitrates are converted into nitrogen gas and ammonia. You need potassium permanganate crystals and calcium sulphate dissolved in water, and then mixed with a substrate. Bacteria cells will form on the substrate then nitrates to nitrogen and ammonia.
What Filtration Devices Can You Use for Nitrate Removal at Home?
Some of the most common filtration devices you can use to remove nitrates from your water at home include:
Jug filters
A jug filter is the most common way for people to reduce their nitrate levels. All you have to do is take a jug, fill it with water, and put some sand in the bottom of it before pouring clean water through the top. This will remove any particles from your drinking water.
Pitcher filters
A pitcher filter can be useful for small homes. or areas with low populations that have to rely on a single water source. This system filters the water through activated charcoal. It is pushed back into the pitcher with a spout for drinking or filling up containers.
If you are in the market for a water filter and pitcher, check out our guide here.
Cartridge Filtration System
This process usually involves a filtration system that has a specific cartridge for removing nitrates from the water, but it can be costly to maintain and replace those cartridges when they are used up. It is also important to note that if you use this method sediment could be left in the water which can lead to health problems.
How to Remove Nitrates from Private Wells
If you have your own well and are concerned about nitrates there are several steps you can take.
First, you should let your water run for a few minutes before using it to flush out any bits of debris or particles that may be increasing the nitrate levels in your well. You also want to make sure that there is not too much silt or dirt at the bottom of your well where bacteria are often present.
If you are looking to purchase a whole house water filter then you will want to find one that has an activated carbon filtration system. The filters can be installed on the main line of your home or in the kitchen, and they will remove nitrates from all water coming into the house.
A septic tank is another way that many well owners have found success removing nitrates from their water. You need to have a septic tank that is large enough for the volume of water that your household consumes on a daily basis. Install an approved sludge blanket at the bottom of the tank before putting any dirt or waste into it.
Once you have the septic tank set up, put a watertight cover on top then install the nitrate filter.
Lastly, drill a hole in the bottom of the plastic container that holds your filter cartridge to allow it to drain into the septic tank as necessary. This will keep nitrates from building up inside of your home’s plumbing system or anywhere else in your home.
Can You Remove Nitrates from Water Using Water Softeners?
If you want to remove nitrates from your water, and save money at the same time, then a water softener is an excellent option. Water can become hard because of minerals such as iron and calcium that get into the system. These minerals cause your water heater to wear out much faster than it typically would.
Water softeners will not only remove the minerals, but also help to reduce the nitrate levels in your water supply.
Our guide to the best water softeners for your home will help you pick the right product for your needs.
How to Test for Nitrates in Your Drinking Water
Nitrates are found in many sources of water, including water for consumption and recreation. You should be cautious when you drink from a public source, and maintain your own filtering system to ensure that nitrate levels don’t get too high. To find out if there are nitrates present in your tap water use testing strips.
There are several types of testing strips available for detecting nitrates in water supplies including sticks with color-coded results, and a strip that will change colors according to nitrate levels detected. The most common type is the stripping stick which features an adhesive on one end so you can place it into a sample of your drinking water.
The strip will change colors depending on the level of nitrates present. It can then be compared with a chart that indicates what levels are considered acceptable in public water supplies. In general, it is recommended to drink from sources with less than 30 parts per million (ppm) of nitrates.
How to Treat Nitrate Contamination
You can treat nitrate contamination by using these methods.
Pretreatment devices
These are typically installed on the main water line before it enters a building. Using these to remove nitrates before they get into the main part of the system can help reduce levels in your home’s well or municipal water supply. The types of pretreatment systems vary depending on what kind of system you have.
Examples of pretreatment devices are gravel beds, air strippers, and ion exchange systems.
Pretreatment devices are often installed with wells because it is difficult to remove nitrates after they have entered the water supply. Nitrogen-removing devices vary in their effectiveness at removing nitrates depending on the type of device used – for example powerful ion exchange systems can remove nitrates from water more quickly than other methods, but they can also cost a lot of money to operate and maintain.
Pump-and-treat systems
These systems are used to remove nitrates from groundwater and wells. A pump is installed at the bottom of your well, or near a septic tank, so that it can take water out of the ground without any risk of contaminating surface waters with nitrate-rich wastewater. The water is then sent to a treatment plant that removes the nitrates.
If you’re interested in this type of system, contact your local municipality for more information on how to obtain and operate it properly.
Municipalities may also have rebate programs available, so be sure to ask about them when inquiring about which pump-and-treat system might work best for you.
Preliminary treatment devices
These work by removing nitrates from the water before it goes into your home’s well or municipal supply. They remove as much of the nitrate toxins as possible, but they are not a substitute for pretreatment systems. Preliminary treatment is mainly designed to remove coarse and large objects in the water before it undergoes pretreatment to eliminate pollutants such as nitrates.
Replacement wells
This is an option if you have high levels of nitrates in your home’s well. You can switch to a new water source that doesn’t have the same level of nitrates, or drill deeper into your existing aquifer for cleaner water.
Removing excess nitrogen
If you’re on a municipal supply and there is no way to get off of it, then your only option may be installing some sort of device in your home to reduce the nitrates in your drinking water. This can be done by a number of products mentioned above.
How to Prevent Nitrate Contamination in Your Water
If you want to be more proactive and prevent nitrate contamination in your water sources, the following steps can help:
- Avoid fertilizers that contain nitrogen when planting new plants
- Seek out organic fertilizers like compost
- Avoid overusing manure fertilizer by adding too much at once
- Maintain an aerated soil to prevent nitrates from leaching into your water supply
- Don’t add food scraps or manure from animals to your compost pile
- Don’t use meat, eggs, or milk products as fertilizer when planting new plants
- Install a drainage field to avoid storm water runoff from washing fertilizers down the street towards your yard and septic tank.
- Make sure to keep your drainage field unobstructed and free of clogs.
- Avoid fertilizing lawns in the winter when rainfall is low.
Take Away
If your well water is sampled and found to be contaminated with nitrates there are ways you can work to fix it. Install a pre-treatment device to remove the contaminants before drinking it. Filter the water as it comes out of the tap. Use an alternative source like bottled water or a municipal supply until you have re-tested your water after improving your filtration systems.
The EPA recommends treating against nitrates in public water supplies that exceed the 10ppb standard, and are home to infants younger than six months or pregnant women at risk of developing low blood oxygen levels. Installation of a pre-treatment device is required if concentrations exceed 5 ppm (parts per million).
Please check out our other articles if you need more information about how to remove nitrates in water.
