Private Water Wells
Summary
A private well supplies a building from groundwater through a drilled bore, casing, grout seal, pump, and pressure system, with the owner responsible for water quality. State and county rules set casing, grouting, setbacks from septic systems and other sources, and abandonment, so the health department's requirements are read before the well and septic layout are fixed.
Cols
Scope
- Source: groundwater from a drilled well on the property
- Delivery: casing and grouted annulus, well cap, pump, pressure tank or controller, and service line to the building
- Regulation: private domestic well water quality is generally not regulated under the Safe Drinking Water Act or by most states; the owner is responsible for delivering safe water; about 15 percent of the US population, over 43 million people, relies on private wells
- Water quality: a USGS study of 2,100 private wells found roughly one in five contained at least one contaminant above a human-health benchmark
Terminology
- Casing: pipe that lines the upper part of the borehole
- Annular space / grout seal: space around the casing, filled with grout to seal it
- Wellhead / cap: sealed top of the well above grade
- Setback: minimum distance from a contamination source
- Pitless adapter: fitting that carries water from the well through the casing below the frost line
- Abandonment / decommissioning: permanent sealing of an unused well
Components
- Borehole, casing, and grout
- Well cap and vent
- Submersible or jet pump
- Pressure tank and controls
- Service line to the building, with a backflow check as required
- Water treatment where testing shows it is needed
Coordination
- Setbacks: the septic system is the primary contaminant source for most private wells; examples of rules include a well within 100 ft of a pollution source such as a septic tank being grouted from at least 50 ft below the surface, with a lower grout requirement for private wells in one state; another state allows a single-family well within 100 ft of a septic system with at least 20 ft of casing and 20 ft of grout; one state ties casing length to setback, requiring longer casing for shorter setbacks
- Casing and grout: casing must be centered in the borehole so filter pack and grout distribute evenly in one state's rules
- Layout: place the well uphill and away from septic fields, fuel tanks, and livestock areas; locate it before locating the septic field and house
- Permits: a well permit and a certified driller are required in many jurisdictions
- Testing: test water at completion and periodically; see EPA's private well guidance
- Locates: call 811 before drilling
Relocation and disconnection
- Moving a well: a new well is drilled and permitted at the new location; the old well is then abandoned; setbacks apply to the new location
- Abandonment: unused wells are sealed so they cannot carry contamination downward; one state describes removing obstructions, pulling or reaming the casing, and piercing casing that cannot be removed
- Sealing: a North Carolina checklist recommends filling the casing bottom to top with neat cement grout or concrete with no voids or bridges, by a certified contractor and not the owner
- Connecting to public water: abandon the well when a public connection is made, unless the code allows both with backflow protection
- Before construction: locate and protect existing wells and plan for the abandonment of any unused well on the site
Manufacturing and cost
Main manufacturers and suppliers
Trade associations: National Ground Water Association and Water Systems Council.
Sources
- U.S. EPA: private drinking water wells, https://www.epa.gov/privatewells
- Mississippi State University Extension: private water wells, https://extension.msstate.edu/sites/default/files/publications/P1815_web.pdf
- North Carolina Division of Public Health: private well rules, https://dph.ncdhhs.gov/media/1079/download
- Virginia Administrative Code: 12VAC5-630-410, https://law.lis.virginia.gov/admincode/title12/agency5/chapter630/section410/
- New Hampshire: Env-Wq 602.16 casing and setbacks, https://regulations.justia.com/states/new-hampshire/we/chapter-we-600/part-we-602/section-we-602-16
- West Virginia University: preventing well contamination, https://actat.wvu.edu/files/d/7d97befe-178a-471e-b12e-6095e52bb318/preventing-well-contamination.pdf
- North Carolina: private well compliance checklist, https://septicandwell.com/downloads/nc-private-well-compliance-checklist.pdf