What it is
A dry well is a buried chamber, often a perforated plastic tank surrounded by gravel, that receives water from a downspout, catch basin or French drain. It stores the water and lets it seep into the surrounding soil over time.
Dry wells work best where soil drains reasonably well and the water table is deep. In slow-draining clay soils, which NRCS soil surveys show are widespread across much of the Houston area, a dry well may fill and stay full, so a professional should test the soil first.
When it is a good fit
- Properties with no legal surface outlet
- Sandier soils that absorb water
- Moderate volumes, such as one or two downspouts
When something else may work better
- Heavy clay or a high water table, where water cannot soak away
- Large volumes that need a continuous outlet
- Areas close to foundations, septic systems or wells
How it is usually installed
- Test how fast the soil absorbs water
- Choose a location away from the house and utilities
- Excavate, line with fabric and set the chamber in gravel
- Connect inlet pipe, add an overflow where possible
- Cover, restore the surface and test
Every property is different. A drainage professional confirms the design onsite. Call 811 before any digging.
What a drainage professional checks first
- Soil infiltration rate and seasonal water table
- Volume of water from the roof or yard area
- Distance from foundations, septic systems and property lines
- Overflow route for large storms
Maintenance
- Keep debris out of inlet pipes
- Clean any filter or inspection port
- Watch for water backing up during long wet periods
What affects the cost
Pricing pending verification
Drainage.net does not publish prices until they have been checked against sourced data. See what drives the cost of dry wells, or request an onsite evaluation for a real quote.
Problems this can help with
Frequently asked questions
Do dry wells work in clay soil?
Often not well. Clay absorbs water slowly, so a dry well can stay full. A soil test before installation shows whether it will work.
Does a dry well need an overflow?
An overflow route is a good idea so that water has somewhere to go when the dry well is full during a long storm.
Sources
This page is educational and does not replace an onsite evaluation. Conditions, codes and HOA rules vary by property.