Single bay hand held spray or brush wand type vehicle washes shall install a 20-gallon per minute (gpm) interceptor minimum.

Multiple bay vehicle washes having hand held spray and/or brush wands must increase interceptor flow capacity by 12 gpm for each additional wash bay at the facility.

Automated drive through car-wash facilities must install an interceptor(s) with a minimum flow capacity of 40 gpm for each wash bay.

To determine the minimum liquid holding capacity (in gallons) for the interceptor, multiply the gpm flow capacity by the standard 12-minute retention time. Depending upon availability, a 15% ± variance between the calculated volume and the interceptor's actual volume is acceptable.

CAR WASH SAND & GREASE INTERCEPTOR SIZING EXAMPLES:

Hand Held Spray/Brush Wand GPM Interceptor Volume May Use
Single Bay 20   250
2 Bay 32   350
3 Bay 44   500
4 Bay 56   750
5 Bay 68   750
6 Bay 80   1000
7 Bay 92   1000
8 Bay 104   1250
9 Bay 116   1250
10 Bay 128   1250
       
Automated Drive Through GPM Interceptor Volume May Use
Single Bay 40 480 500
2 Bay 80 960 1000
3 Bay 120 1440 1500
4 Bay 160 1920 2000