Radon in Water, testing for radon, glass of water, The Radon SpecialistRadon in Water

Radon gas can also enter homes through the water supply. Radon dissolves and builds up in water from underground sources, such as wells. The radon in your water can enter the air in your home when you use water for household activities such as showering, washing clothes and cooking. For every 10,000 picocuries per liter (pCi/L) of radon in your water, it is estimated that 1 pCi/L is added to your radon in the air. If your water comes from a lake, river, or reservoir (surface water), radon is not a concern. The radon is released into the air before it reaches your home. Some states like Connecticut, New Hampshire and Vermont recommend fixing radon in water if the levels are above 5000 pCi/L.

The North Carolina Radon Program recommends a radon-in-water advisory be set at two levels. At the moderate level, concentrations between 4,000 and 10,000 pCi/L in water, treatment is considered optional. At the elevated level, concentrations at or above 10,000 pCi/L in water, treatment should be considered in conjunction with the treatment of indoor air radon released from soil gas. In most cases, mitigation of soil gas radon will have the greatest impact on reducing overall radon exposure and will usually take precedence over treatment of radon in water.

Some radon stays in the water. Radon in the water you drink can also contribute to a very small increase in your risk of stomach cancer. However this risk is almost insignificant compared to your risk of lung cancer from radon.

It is suggested by the EPA that if you have elevated air radon levels and are on a private well, you should have your water radon tested.

Removal of Radon from Water

There are only two practical techniques for removing radon from water in a residential setting. One technique uses activated carbon. The carbon adsorbs the radon from the water. The radon then finishes decaying in the carbon. Activated carbon should only be used if the radon water levels are below 5000 pCi/L. This low level is recommended by the EPA because of the concern over the buildup of radioactivity.

Aeration systems are is used on very high levels of radon. The radon is released from the water by bubbling air through the water. The radon is then vented to the outdoors. There is no buildup of radioactive materials when this technique is used. The removal of well over 99% of the radon from the water can be achieved with these units. These units do require the repressurization of the water after it is treated and care must be taken to properly vent the gas. This venting should be done above the roof line just like an air radon system and there should always be an auxiliary fan outside of the living space to provide for the save removal of the gas. Water aeration is considered by the U.S. EPA to be the best available technology for removing radon from well water. Unlike other methods, such as granular activated carbon tanks, aeration does not pose the threat of waste buildup.

Schedule an appointment to have your water tested for Radon



Radon Mitigation Systems 

Home Foundation Types

Your home type will affect the kind of radon reduction system that will work best. Homes are generally categorized according to their foundation design. For example: basement, slab, concrete poured at ground level; or crawlspace, a shallow unfinished space under the first floor. Some homes have more than one foundation design feature. For instance, it is common to have a basement under part of the home and to have a slab-on-grade or crawlspace under the rest of the home. In these situations a combination of radon reduction techniques may be needed to reduce radon levels to below 4.0 pCi/L.

The Radon Specialist, Types of home foundations that can be treated for RadonRadon reduction systems can be grouped by home foundation design. Find your type of foundation design above and read about which radon reduction systems may be best for your home.

Basement and Slab Homes

In homes that have a basement or a slab foundation, radon is usually reduced by one of four types of soil suction: sub-slab or block-wall suction depressurization system.

Active Sub-slab suction — also called sub-slab depressurization — is the most common and usually the most reliable radon reduction method. One or more suction pipes are inserted through the floor slab into the crushed rock or soil underneath. They also may be inserted below the concrete slab from outside the home. The number and location of suction pipes that are needed depends on how easily air can move in the crushed rock or soil under the slab and on the strength of the radon source. Often, only a single suction point is needed.

We usually get our information from a visual inspection, from diagnostic testing, and/or from our experience. A radon vent fan connected to the suction pipes draws the radon gas from below the home and releases it into the outdoor air while simultaneously creating a negative pressure or vacuum beneath the slab. Common fan locations include unconditioned home and garage spaces, including attics, and the exterior of the home.

Some homes have drain tiles or perforated pipe to direct water away from the foundation of the home. Suction on these tiles or pipes is often effective in reducing radon levels.

One variation of sub-slab and drain tile suction is sump-hole suction. Often, when a home with a basement has a sump pump to remove unwanted water, the sump can be capped so that it can continue to drain water and serve as the location for a radon suction pipe.

Block-wall suction can be used in basement homes with hollow block foundation walls. This method removes radon and depressurizes the block wall, similar to sub-slab suction. This method is often used in combination with sub-slab suction.

The Radon Specialist, Greensboro, Radon Entry Diagram WorkplaceCrawlspace Houses

An effective method to reduce radon levels in crawlspace homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called sub-membrane suction, and when properly applied is the most effective way to reduce radon levels in crawlspace homes.

Another less-favorable option is active crawlspace depressurization which involves drawing air directly from the crawlspace using a fan. This technique generally does not work as well as sub-membrane suction and requires special attention to combustion appliance back drafting and sealing the crawlspace from other portions of the home, and may also result in increased energy costs due to loss of conditioned air from the home.

In some cases, radon levels can be lowered by ventilating the crawlspace passively, or actively, with the use of a fan. Crawlspace ventilation may lower indoor radon levels both by reducing the home's suction on the soil and by diluting the radon beneath the home. Passive ventilation in a crawlspace is achieved by opening vents, or installing additional vents. Active ventilation uses a fan to blow air through the crawlspace instead of relying on natural air circulation. In colder climates, for either passive or active crawlspace ventilation, water pipes, sewer lines and appliances in the crawlspace may need to be insulated against the cold.

  • National Radon Safety Board, Radon Specialist, Greensboro, NC

  • National Radon Proficiency Program, NEHA, Radon Specialist, Greensboro, NC

  • AARST member logo, Radon Specialist, Greensboro, NC