Water Harvesting: Rain Barrels and Cisterns
Rain barrels and cisterns collect and temporarily store rainwater from roofs. This water can be used to water gardens, lawns, and trees. Rainwater enters them from gutters and downspouts and there is an outlet that can be connected to a garden hose. When they overflow, excess water is directed away from the building to a location on the property where it can soak into the ground.
Why Should I Install a Rain Barrel or Cistern?
By collecting your roof runoff in rain barrels or cisterns, you can reduce polluted stormwater runoff from your property. Stormwater runoff is reduced, because you are collecting the stormwater and allowing it to soak into the ground when you use it for irrigation.
When you use the rainwater to water your gardens and landscaping, you also use less potable (tap) water for this purpose, which can lower your water bills. Since rain barrels and cisterns collect rainwater for use on site, they can reduce the harmful effects to streams caused by large and rapid stormwater runoff flows.
What is the Difference Between a Rain Barrel and Cistern?
Rain barrels come in a variety of sizes but typically as a 55-gallon container that collects roof runoff. Rain barrels can be added to any building with gutters and downspouts. All rain barrels require an overflow port. Rain barrels are usually around the size of a trash can, but cisterns can be much larger, ranging from the size of a washing machine to a car, to collect and store more water.
To be eligible for a RainScapes Rewards Rebate, the total rain barrel capacity on your property must be at least 200 gallons.
Cisterns are sealed tanks that can be located above ground, partially buried, or below ground. Cisterns are larger than rain barrels and they can collect water from several downspouts from one building’s roof or from multiple roofs if they are large enough. Large cisterns may require a permit, so please check with the County’s Department of Permitting Services. When cisterns or rain barrels are full, the overflow should be directed to a safe location away from the building foundation. Overflow may also connect into a dry well, rain garden, or other area where the runoff can infiltrate into the ground on your property. To be eligible for a RainScapes Rewards Rebate, a cistern must be a above ground stand-alone system for landscape applications and non-domestic use, and there must be sufficient space on your lot to accomodate overflow.
To avoid mosquitoes, rain barrels and cisterns should be emptied within 1 week of a rain event.
Water collected in rain barrels or cisterns is for non-potable, exterior uses only; the County does not currently permit hooking these devices into your home’s sewer system for actions such as toilet flushing. Cisterns may be connected to existing stormdrain systems, but it is expensive to do so and a direct connection will require a permit.
Cisterns may require an electric pump to empty out the water, which may require a permit from the County’s County’s Department of Permitting Services. Contact Permitting Services to obtain information about the necessary right-of-way and other applicable permits to connect to a public storm drain system.
Is a Rain Barrel or Cistern Right for Me?
Rain barrels and cisterns are often the first stormwater management practice installed on properties, because they are relatively inexpensive, useful for watering gardens and they don't require a lot of space. They may not be suitable for your property if you do not have access to a downspout, or you do not think you could provide regular maintenance.
Rain barrels and cisterns:
How to Assess Your Property
Take some time to walk around your property to assess your roof gutter and downspout system. Do this 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 property’s drainage conditions:
Ready to move ahead with installing rain barrels or a cistern?
Many rain barrels can be installed without a contractor. If you would like to hire a contractor, download the Rain Barrel and Cistern Guide (below) for helpful questions to ask and other information.
There are a lot of decisions that need to be made with your rain barrel and cistern after the assessment is complete.
The RainScapes Rain Barrel and Cistern 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 Rewards Rebates program with great financial incentives for installing the rain barrels or cisterns.
Watch a Video from a Rain Barrel Make-and-Take Workshop
Maintaining Rain Barrels and Cisterns
DEP can answer your questions and provide additional guidance about maintaining your rain barrel or cistern. Please email email@example.com, call the Montgomery County Customer Service Center at 3-1-1.
Rain Barrels and Cisterns 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 transfered 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 rain barrel or cistern 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 these facility locations as part of the Stormwater Facility Maintenance Program. DEP may perform a maintenance inspection of your practice if it is a permitted structure. Rain barrels and cisterns that are part of the Stormwater Facility Maintenance Program must contact DEP before any major changes can be performed to the structure.
Rebates, Resources and Financial Incentives
Interested in installing rain barrels or a cistern? The County offers incentives to help make the decision a little easier.
The RainScapes 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 rain barrels and cisterns.
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 rain barrels and cisterns. They have a wealth of information, expertise and want to help!
The Water Quality Protection Charge Credit Program
After you have installed your rain barrel or cistern, 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 rain barrel 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.
Cisterns provide a large credit, while rain barrels provide the smallest credit of any stormwater facility practice. The low credit is because rain barrels divert the least amount of stormwater of any practice.