Dry well sizing and permits

Have the proposed location assessed for infiltration, seasonal groundwater, nearby structures and sensitive systems. Clay, saturated soil or limited separation may make a dry well unsuitable. Ask the local authority which drainage or stormwater approvals apply.

A generic distance from a building is not a substitute for local and product requirements.

NDS lists 50 gallons of storage for one Flo-Well chamber. That product number does not establish how much roof or yard it can serve. Runoff volume, infiltration rate, contributing area and the design storm determine the required system.

The surrounding stone, chamber layout and overflow also affect performance.

Ask how leaves and sediment are kept out and where excess water goes when storage is full. Keep inspection or service access reachable. A blocked inlet or saturated receiving soil can prevent the system from working even if the chamber itself is intact.

The illustration shows the concept, not a chamber sizing or excavation detail.

The published price band below is a basic planning allowance, not a promise for engineered stormwater storage. Rock excavation, multiple chambers, testing, permits and long pipe runs can change the project materially. Do not add a dry-well outlet charge when the selected job already prices that same well.

010203

01Filter fabric

Nonwoven fabric keeps soil out of the gravel so the drain doesn't clog.

02Clean gravel

Washed gravel around the pipe lets water reach it from every side.

03Perforated pipe, holes down

Water rises into the holes and runs along the pipe, which slopes toward the outlet.

• S&S Excavation — published Kansas City French drain rates, checked 2026-10-26
• HomeGuide — French drain cost, checked 2026-10-26
• HomeGuide — drainage system installation cost, checked 2026-10-26
• Ledge — catch basin estimating, checked 2026-10-26
• HomeGuide — cost to level or regrade a yard, checked 2026-10-26
• Richmond Retaining Wall Company — grading planning rates, checked 2026-10-26