Well Construction and Grouting
The Well Construction and Grouting domain tests siting, casing and screen design, the annular seal and the wellhead: the parts an inspector can measure. Construction errors surface years later as bacterial contamination or a well that pumps sand.
Siting under the Connecticut Public Health Code (RCSA 19-13-B51)
- Generally at least 25 ft from a property line, 50 ft from any part of a subsurface sewage disposal system, and 10 ft from a building foundation; local health departments may require more.
- Locate upslope of the disposal area and away from drainage paths, driveways, fuel storage and animal pens.
- The local director of health issues the well permit before drilling begins.
Casing, screen and gravel pack
Steel or PVC casing sized for the pump; screen slot chosen to retain the gravel pack, with pack grain size roughly 3 to 4 times the slot opening. Screen the producing interval, not the whole hole, and cap the bottom.
The annular seal
Neat cement or bentonite grout placed by tremie or positive-displacement pump from the bottom of the casing upward, continuous to grade. Never drop bentonite chips into a deep annulus and assume they seal; they bridge and leave voids.
Wellhead
Pitless adapter below the frost line (about 42 in. in Connecticut), vermin-proof cap, casing terminating at least 12 in. above grade or above the pit floor, and ground sloped away from the casing.
Worked example
A site plan shows the well 22 ft from the property line, 45 ft from the edge of the leaching field and 8 ft from the foundation. All three fail against the 25, 50 and 10 ft minimums. Relocate so the well clears 25 ft to the line, 50 ft to the nearest edge of the disposal system (measured to the leach field, not the tank) and 10 ft from the foundation, then confirm the new spot is upslope of the field and outside the driveway before resubmitting the plan.
Traps that cost marks
- Measuring the sewage setback to the tank instead of the disposal area.
- Computing grout volume from nominal hole diameter when the hole was washed out and oversized.
- Setting the pitless adapter above the frost line.
- Terminating casing too low so surface water reaches the annulus.