Simple rooftop connections are generally not advisable for residential lots with an area less than how many square feet?

Simple rooftop connections are generally not advisable for residential lots with an area less than how many square feet?

• A. 4,000 square feet
• B. 8,000 square feet
• C. 6,000 square feet
• D. 10,000 square feet

Answer: (C)

Rooftop runoff should be kept on-site whenever possible, especially on smaller parcels. For residential lots with limited area, there isn’t enough space to store, infiltrate, or treat the additional water from a roof, so a simple rooftop connection to the storm system can lead to higher peak flows and potential downstream problems. The threshold of 6,000 square feet is used because below that size, the on-site area generally cannot adequately detain or infiltrate the roof runoff, making such connections inadvisable. On smaller lots, prefer options like disconnecting downspouts to permeable surfaces, rain barrels, or on-site infiltration features to manage the water. Larger lots have more area to accommodate on-site management, so simple rooftop connections are typically more acceptable when other criteria are met.

Rooftop runoff should be kept on-site whenever possible, especially on smaller parcels. For residential lots with limited area, there isn’t enough space to store, infiltrate, or treat the additional water from a roof, so a simple rooftop connection to the storm system can lead to higher peak flows and potential downstream problems. The threshold of 6,000 square feet is used because below that size, the on-site area generally cannot adequately detain or infiltrate the roof runoff, making such connections inadvisable. On smaller lots, prefer options like disconnecting downspouts to permeable surfaces, rain barrels, or on-site infiltration features to manage the water. Larger lots have more area to accommodate on-site management, so simple rooftop connections are typically more acceptable when other criteria are met.