Choose a contractor to fix a radon problem just as you would choose someone to do other home repairs. It is wise to get more than one estimate, to ask for references, and to contact some of those references to ask if they are satisfied with the contractors' work.

New York State Department of Health does not regulate radon services. Ask the contractor if they hold a professional proficiency or certification credential, and if they follow industry consensus standards such as ANSI/AARST SGM-SF-2017 Soil Gas Mitigation Standards for Existing Homes or the American Society for Testing and Materials, ASTM, Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings, E2121.

• Evaluate and Compare Contractors

  Ask the following questions and then use this checklist when evaluating and comparing contractors:

  YES	NO	Question
  		Will the contractor provide references or photographs, as well as test results of before and after radon levels of past radon reduction work?
  		Can the contractor explain what the work will involve, how long it will take to complete, and exactly how the radon reduction system will work?
  		Does the contractor charge a fee for any diagnostic tests? Although many contractors give free estimates, they may charge for diagnostic tests. These tests help determine what type of radon reduction system should be used and in some cases are necessary, especially if the contractor is unfamiliar with the type of home structure or the anticipated degree of difficulty. See "Soil Gas Mitigation Standards for Existing Homes" for more on diagnostic tests.
  		Did the contractor inspect your home's structure before giving you an estimate?
  		Did the contractor review the quality of your radon measurement results and determine if appropriate testing procedures were followed?

• Compare Contractors' Costs

  Compare the contractors' proposed costs and consider what you will get for your money, taking into account: a less expensive system may cost more to operate and maintain; a less expensive system may have less aesthetic appeal; a more expensive system may be best for your home; and, the quality of the building material will affect how long the system lasts.

  YES	NO	Does the contractor's proposal and estimate include?
  		Proof of professional proficiency or certification credentials?
  		Proof of liability insurance and being bonded, and having all necessary licenses to satisfy local requirements?
  		Diagnostic testing prior to design and installation of a radon reduction system?
  		Installation of a warning device to caution you if the radon reduction system is not working correctly?
  		Testing after installation to make sure the radon reduction system works well.
  		A guarantee to reduce radon levels to 4 pCi/L or below. And if so, for how long?

• The Contract

  Ask the contractor to prepare a contract before any work starts. Carefully read the contract before you sign it. Make sure everything in the contract matches the original proposal. The contract should describe exactly what work will be done prior to and during the installation of the system, what the system consists of, and how the system will operate. Many contractors provide a guarantee that they will adjust or modify the system to reach a negotiated radon level. Carefully read the conditions of the contract describing the guarantee. Carefully consider optional additions to your contract which may add to the initial cost of the system, but may be worth the extra expense. Typical options might include an extended warranty, a service plan and/or improved aesthetics.

  Verified	Does the Contract Include?
  	The total cost of the job, including all taxes and permit fees; how much, if any, is required for a deposit; and when payment is due in full.
  	The time needed to complete the work.
  	An agreement by the contractor to obtain necessary permits and follow required building codes.
  	A statement that the contractor carries liability insurance and is bonded and insured to protect you in case of injury to persons, or damage to property, while the work is done.
  	A guarantee that the contractor will be responsible for damage and cleanup after the job.
  	Details of any guarantee to reduce radon below a negotiated level.
  	Details of warranties or other optional features associated with the hardware components of the mitigation system.
  	A declaration stating whether any warranties or guarantees are transferable if you sell your home.
  	A description of what the contractor expects the homeowner to do, such as make the work area accessible, before work begins.

In homes that have a basement or a slab-on-grade foundation, radon is usually reduced by one of four types of soil suction:

• subslab suction
• drain-tile suction
• sump-hole suction
• block-wall suction

• Subslab Suction

  • Active Subslab Suction

    Active subslab suction — also called subslab 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.

    A contractor usually gets this information from visual inspection, from diagnostic tests, and/or from 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.

  • Passive Subslab Suction

    Passive subslab suction is the same as active subslab suction except it relies on natural pressure differentials and air currents instead of a fan to draw radon up from below the home. Passive subslab suction is usually associated with radon-resistant features installed in newly constructed homes. Passive subslab suction is generally not as effective in reducing high radon levels as active subslab suction.

• Drain-Tile Suction

  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.

• Sump-Hole Suction

  One variation of subslab 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

  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 subslab suction. This method is often used in combination with subslab suction.

• Crawlspace Ventilation

  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. These ventilation options could result in increased energy costs for the home.

  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 submembrane 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 submembrane suction and requires special attention to combustion appliance backdrafting 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.

Additional Radon Reduction Techniques

Other radon reduction techniques that can be used in any type of home include:

• sealing
• home or room pressurization
• heat recovery ventilation
• natural ventilation

• Sealing

  Sealing cracks and other openings in the foundation is a basic part of most approaches to radon reduction. Sealing the cracks limits the flow of radon into your home, thereby making other radon reduction techniques more effective and cost-efficient. It also reduces the loss of conditioned air. EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently. It is difficult to identify and permanently seal the places where radon is entering. Normal settling of your home opens new entry routes and reopens old ones.

• Home or Room Pressurization

  Home or room pressurization uses a fan to blow air into the basement, or living area from either upstairs or outdoors. It attempts to create enough pressure at the lowest level indoors — in a basement, for example — to prevent radon from entering into the home. The effectiveness of this technique is limited by home construction, climate, other appliances in the home and occupant lifestyle. In order to maintain enough pressure to keep radon out, the doors and windows at the lowest level must not be left open, except for normal entry and exit. This approach generally results in more outdoor air being introduced into the home, which can cause moisture intrusion and energy penalties. Consequently, this technique should only be considered after the other, more-common techniques have not sufficiently reduced radon.

• Heat Recovery Ventilation

  A heat recovery ventilator, or HRV, also called an air-to-air heat exchanger, can be installed to increase ventilation which will help reduce the radon levels in your home. An HRV will increase ventilation by introducing outdoor air while using the heated or cooled air being exhausted to warm or cool the incoming air. HRVs can be designed to ventilate all or part of your home, although they are more effective in reducing radon levels when used to ventilate only the basement. If properly balanced and maintained, they ensure a constant degree of ventilation throughout the year. HRVs also can improve air quality in homes that have other indoor pollutants. There could be significant increase in the heating and cooling costs with an HRV, but not as great as ventilation without heat recovery.

• Natural Ventilation

  Some natural ventilation occurs in all homes. By opening windows, doors, and vents on the lower floors you increase the ventilation in your home. This increase in ventilation mixes outdoor air with the indoor air containing radon, and can result in reduced radon levels. However, once windows, doors and vents are closed, radon concentrations most often return to previous values within about 12 hours. Natural ventilation in any type of home should normally be regarded as only a temporary radon reduction approach because of the following disadvantages: loss of conditioned air and related discomfort; greatly increased costs of conditioning additional outside air; and security concerns.

Radon in Water

Radon in water is usually not the primary source of radon in the home. If a radon in air mitigation system appears not to be reducing radon levels, then radon in water may be evaluated as a pathway. Presently there is no guideline or recommended action level for radon in water concentration. Radon in water may pose an inhalation risk. This risk results when radon is released into the air when water is used for showering and other household purposes. Approaches to mitigate radon in water are aeration or filtration using granular activated carbon.

Effectiveness

Single Family Housing Repair Loans and Grants (Section 504 Program)

Provides loans to very-low income homeowners to repair, improve or modernize their homes and grants to elderly very-low income homeowners to remove health and safety hazards. The maximum loan is $40,000 and can be repaid over 20 years with a fixed interest rate of 1%. A real estate mortgage is required for loans of $7,500 or more. For grant consideration, the applicant must be 62 or older and not able to repay a repair loan. Grants have a lifetime limit of $10,000 but can be combined with a loan for up to $50,000 in assistance. Grants must be repaid if the property is sold in less than 3 years. For additional information: https://www.rd.usda.gov/programs-services/single-family-housing-repair-loans-grants

Direct and Guaranteed Single Family Housing Loans (Section 502 Program)

Provides low- and moderate-income households the opportunity to purchase or build modest, decent, safe and sanitary dwellings in eligible rural areas. These two loan programs provide home purchase financing but can also support qualifying housing rehabilitation. Household income determines if applicants qualify for a loan directly from USDA Rural Development or from a participating financial institution.

Section 502 Direct Loans

Available to low income households as defined as 80% of the HUD median income limit. No down payment is required, and USDA can finance up to 100% of the appraised value. The standard term for a Section 502 Direct Loan is 33 years. Loans are made at a fixed rate established by the Agency; payment subsidies are available to qualifying borrowers to reduce loan payments. Private mortgage insurance (PMI) is not required. For additional information, please visit: https://www.rd.usda.gov/programs-services/single-family-housing-direct-home-loans

Guaranteed Rural Housing Loan

This program assists approved lenders in providing low- and moderate-income households the opportunity to purchase or build modest homes in rural areas. The program provides a 90% loan note guarantee to approved lenders in order to reduce the risk of extending 100% loan to value financing to eligible homebuyers. These loans are made at a competitive fixed rate of interest and are repaid over 30 years. Private mortgage insurance (PMI) is not required, but a guaranteed fee is required at closing, which can be financed above the appraised value. For additional information, please visit:https://www.rd.usda.gov/programs-services/single-family-housing-guaranteed-loan-program

Housing Preservation Grants (Section 533 Program)

Provides grants to sponsoring organizations for the repair or rehabilitation of housing owned or occupied by low and very low-income rural citizens. Eligible applicants include most state and local government agencies, nonprofit organizations and federally recognized tribes. The grantee must have the necessary background and experience with proven ability to perform the responsibility of repair rehabilitation of low-income housing. Funds can be used by the grantee to provide grants or low interest loans to income qualifying rural homeowners or to rental property owners if they agree to make units available to low income families. Areas to be served have a population limit of 20,000. For additional information, please visit: https://www.rd.usda.gov/programs-services/housing-preservation-grants

For all USDA Rural Development Program, State and Local Contact Information, please visit: https://www.rd.usda.gov/

Below is a list of basic installation requirements that your contractor should meet when installing a radon reduction system in your home. It is important to verify with your contractor that the radon mitigation standards (ASTM E2121 in particular) are properly met to ensure that your radon reduction system will be effective.