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New Hampshire Department of Environmental Services

Wellhead Protection Tips for Small Public Water Systems
Small public water systems such as residential subdivisions, apartment buildings, schools, or workplaces should take steps to protect their wells from contamination. Wellhead protection begins with the owner and operator of a well. To achieve protection, follow the five steps listed below and explained in further detail in this flier
1. Protection Areas

Sanitary Protective Radius

This area should receive the greatest attention. The Sanitary Protective Radius is a 75 - 400 foot radius around the well which under current law must be controlled by the water supplier through ownership or easement. The extent of the Sanitary Protective Radius depends on the maximum daily amount of water withdrawn from the well. Know the extend of your Sanitary Protective Radius, and be sure only activities that are both directly related to your water system and non-threatening to the water quality occur within the radius. Regularly inspect your Sanitary Protective Radius to be sure the water supply is not being threatened.

Wellhead Protection Area

The area under which groundwater flows to a producing well is known as the Wellhead Protection Area (WHPA). For bedrock wells, the WHPA is a circle whose radius depends on the maximum daily amount of water withdrawn from the well. For till and gravel wells, the WHPA has been calculated based on existing hydrogeologic information.

2. Examine Activities

Look carefully at activities and businesses within the Wellhead Protection Area. Identify any threats to water quality and develop strategies to address them. Be sure to include:

Underground Storage Tanks (USTs) - Leaking oil and gasoline USTs contaminate soil and groundwater. If a UST is located within the Sanitary Protective Radius of a well, remove it to a location outside the Sanitary Protective Radius and check for signs of previous spills or leaks. (Call NHDES Regarding UST closure rules). If you need to store fuel to power an emergency generator, use natural gas or propane. Any heating oil tanks in the larger WHPA should be in above-ground or basement tanks located on an impermeable surface and contained in an area large enough to hold the complete liquid volume should a spill occur.

Herbicides, Pesticides, and Fertilizers - Herbicides and pesticides must not be used or stored within your Sanitary Protective Radius. If you use them outside of but near the Sanitary Protective Radius, be careful to follow specific guidelines, which vary depending upon the quantity and types of products you choose to apply. Fertilizers are potential sources of nitrates and bacteria; don't use them in the Sanitary Protective Radius. Contact Pierce Laskey-Rigrod at for more information.

Septic Systems - Septic tanks, leach fields, etc., should be removed and placed outside the Sanitary Protective Radius of a well. Septic systems outside of but near the Sanitary Protective Radius should be well-maintained. Inspect septic tanks every year and pump when needed. Never dump hazardous household chemicals down the drains. Do not use septic system cleaners.

Storage areas - Do not store hazardous substances that are not essential to the operation of your treatment system (i.e. gasoline, garden chemicals, paints, deicers/salt, motor oil, or antifreeze) within a Sanitary Protective Radius, either indoors or outdoors. Outside the Sanitary Protective Radius, store them in a secure building equipped with an impermeable floor and with adequate spill containment equipment.

Parking and Vehicle Use - Do not establish a parking area in the Sanitary Protective Radius. Perform maintenance and washing of vehicles outside the Sanitary Protective Radius. Keep any vehicles that must operate in the Sanitary Protective Radius in good repair to prevent leaks and spills. Thoroughly clean up any leaks or spills immediately.

Municipal/Institutional Systems - Your own facility may be carrying out some of the potentially harmful activities listed above. In addition, your system may use hazardous substances or produce hazardous waste. Inspect your facilities, record what is being used, and be sure hazardous materials are stored and disposed of properly.

For example, at a school, be sure that:

  • Art supplies are properly stored and hazardous wastes produced by the art studio are not discharged through the sink;
  • Laboratory chemicals are properly stored and disposed of; and
  • Waste oils and antifreeze from the automotive shop are properly labeled, stored, and disposed of.
3. Good Management

A well must be secure and protected. To ensure the safety and purity of the well,


  • Regularly inspect activities in the Sanitary Protective Radius;
  • Restrict access to the well (for community systems);
  • Clearly label any hazardous materials (essential to your treatment system) located near the well;
  • Cap and/or screen all vents, access ports, and other openings of the well;
  • Check the condition of sanitary seals and replace those that are not intact;
  • Slope parking areas and concrete pads under storage areas away from the well, periodically check their condition, and repair any permeable area;
  • Safeguard chemical feeders from inadvertent physical disturbances or tampering;
  • Use a properly constructed sample tap and take other measure to avoid cross-connections; and
  • Inspect back flow prevention valves and replace as needed.


  • Allow the installation of floor drains that discharge to a dry well or any surface leaching system (except for water system back flush) within the Sanitary Protective Radius;
  • Store any type of chemical in or near the well house; or
  • Risk cross-connections by using a hose bib as your sample tap or allowing hoses to be submerged in swimming pools or slop sinks.
4. Municipal Officials

Be sure that town officials know you operate a public water system. Explain the exact location of your well, your Sanitary Protective Radius, and your WHPA. You may be able to work with town officials to educate residents and businesses within your WHPA and to reduce threats from town-wide activities such as road salting. Ask that your WHPA be included in any groundwater protection planning efforts. If you are concerned about a particular activity near your well, ask the Health Officer or Code Enforcement Officer for help in informing the property owner about Best Management Practices for groundwater protection.For more information, contact Pierce Laskey-Rigrod at for more information.

5. Educate

It is critical to water supply protection that the public be aware of a protection area. Post signs at access routes entering the WHPA to inform visitors that they are entering a sensitive area. Use periodic mailings to educate residents and businesses in your WHPA about the importance of protecting groundwater. Inform your staff and your water users about potential threats; they may help you locate and resolve a problem. DWGB can provide you with sample notices to post within your facility to remind your staff that they are within the protected area of a water supply.


Wells with an approved wellhead protection plan are eligible for money-saving Phase II/V Monitoring Waivers. Also, protecting your source saves you the added expense of water treatment associated with contamination. Ultimately, the protective measures you take help protect your investment and ensure healthy drinking water.

NH Department of Environmental Services | 29 Hazen Drive | PO Box 95 | Concord, NH 03302-0095
(603) 271-3503 | TDD Access: Relay NH 1-800-735-2964 | Hours: M-F, 8am-4pm

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