You can implement a few features on your property to gain credit.
Rain barrels harvest and store water from your rooftop by collecting it from a gutter downspout. The stored runoff can be used for watering or other purposes that don't require drinking water. Rain barrels offer several advantages. Using the runoff for watering can reduce your water bill, benefit your plants, and help rain percolate into the ground and recharge groundwater supplies. A credit equal to 100 sft of impervious area per rain barrel is in use.
Rain gardens are planted depressions of deep-rooted native vegetation designed to absorb excess rainwater runoff from a house or other impervious area with the purpose (besides being beautiful) of allowing rainwater to pool in a low spot just long enough to percolate into the ground. Cisterns are water management devices that provide retention storage volume in above or underground storage tanks.
Cisterns are often larger than rain barrels, with some underground cisterns having a capacity of 10,000 gallons. Only one credit can be taken for utilizing a dry well or cistern.
Drywells are small, excavated pits backfilled with aggregate and used to infiltrate “good quality” stormwater runoff, such as uncontaminated roof runoff. Drywells are not to be used for infiltrating any runoff that could be significantly contaminated with sediment and other pollutants, such as runoff from high-potential pollutant loading areas and parking lot runoff. Only one credit can be taken for utilizing a dry well or cistern. Credit for these depends on the design capacity for each.