A dry well is an underground area that is filled with stone or gravel. Once water enters the dry well, it passes through the stone or gravel and then seeps into the underlying soil.
A dry well collects stormwater from rooftops or hard surfaces, such as your driveway. An underground pipe directs runoff from roof downspouts into the dry well.
Dry wells reduce stormwater runoff, promote infiltration and groundwater recharge, and filter pollutants. Sometimes a proprietary storage device is used to increase storage efficiency and decrease the footprint of the dry well.
Why Should I Install a Dry Well?
Directing roof or driveway runoff to a dry well is an effective way to reduce stormwater runoff from your property, because you are capturing the stormwater and allowing it to soak into the ground. Dry wells are underground features that work well in areas where space is limited. Dry wells generally do not impact the visual appeal of your property as they are located along your driveway or underground and may be covered with soil and sod or other shallow-rooted plants.
However, the most important reason to install a dry well may be that you are doing your part to help the environment and protect your local streams and the Chesapeake Bay.
Dry wells can be installed under voluntary programs like the DEP Rainscapes program, or may be permitted under your building's construction.
Is a Dry Well Right for Me?
Not all properties are suitable for a dry well.
How to Assess Your Property for a Dry Well
Assess your roof gutter and downspout system by walking around your property. Make your observations when it is raining, so you can see where the rain lands on your property and where it flows. Follow these basic steps to identify your site’s drainage conditions:
To Collect Roof Runoff
To Collect Driveway Runoff
Installing Your Dry Well
Ready to move ahead with installing a dry well?
There are a lot of decisions that need to be made with your dry well after the assessment is complete.
The RainScapes Dry Well Guide (below) has suggestions and useful information on how to best make the necessary decisions. The RainScapes program has knowledgeable and helpful staff who can help you through the process as well as the RainScapes Rebates program with great financial incentives for installing the dry well.
Maintaining Dry Wells
As the property owner, you are responsible for all maintenance of your dry well unless a shared maintenance agreement has been made with the DEP Stormwater Facility Maintenance Program.
An un-maintained dry well may:
DEP can answer your questions and provide additional guidance about maintaining your dry well. Please email email@example.com or call the Montgomery County Customer Service Center at 3-1-1.
Dry Wells in the Stormwater Facilities Maintenance Program
The Stormwater Facilities Maintenance Program is responsible for maintaining all public stormwater facilities as well as all private facilities that transferred their maintenance to the County. The program also maintains facilities that were required as part of the Department of Planning permits.
Can I remove my dry well after installation?
No, you cannot remove any facilities that were part of your building installation - these are permitted structures and DEP maintains a database of thesefacility locations as part of the Stormwater Facility Maintenance Program. DEP may perform a maintenance inspection of your practice if it is a permitted structure. Property owners must contact DEP before any major changes can be performed to the structure.
Rebates, Resources and Financial Incentives
Interested in installing a dry wellf? The County offers incentives to help make the decision a little easier.
The RainScapes Rewards Rebates Program
The County offers technical and financial assistance (in the form of rebates) to encourage property owners to implement RainScapes techniques on their property, including dry wells.
To participate, your property must be located in Montgomery County, outside of the municipal limits of the City of Rockville, City of Takoma Park, or City of Gaithersburg. Projects are not eligible if they are associated with permit approval requirements for new building construction, additions, or renovations.
The program is funded each fiscal year (The FY begins July 1 and ends June 30). Annual funds for the programs are limited, so rebates will be awarded on a first-come-first-served basis.
The RainScapes program also provides technical assistance to help with the installation of your dry well. They have a wealth of information, expertise and want to help!
The Water Quality Protection Charge Credit Program
After you have installed your dry well, you are now eligible to receive a credit off your annual Water Quality Protection Charge (found on your yearly property tax bill). The credit provides an incentive for maintaining your dry well and other stormwater management practices.
You must apply for the WQPC credit separately – the credit will not be provided to you automatically.
Residential property owners can receive up to 50% off their WQPC depending on the type and size of stormwater management practices on the property.
Non-residential and multi-family properties can receive up to 50-60% off their WQPC depending on the type and size of the stormwater management practices on the property.