Reference Document MCU22/0102 Stormwater Management Plan

5.3. CAR WASH WATER USE MODEL
The water usage requirements for the different types of wash bays varies substantially (ie:
automatic wash bays can use 5 times the amount of water than self-serve wash bays), as does
the water usage for the different brands/manufacturers of car washing equipment that can be
specifically installed on a Car Wash site. The below data is based on the Automatic wash bays
being the PDQ Laserwash 360+, the Self-Serve wash bays being the Prowash iWash Classic, and
the Dog Wash unit being a K9000 Twin dog wash unit.
Table 1 (below) specifies the different use areas of the Car Wash and lists the typical mains water
demand volume requirement per wash. The Auto Bay with Reclaim (Recycling) shows how
much recycled water and fresh (mains) water can be used in each car wash cycle. An adjustment
is made for water losses through drive off of between 10-15% (depending on the wash bay
type). Finally, the volume of effluent water that is discharged to sewer is listed. You can see how
great the variation is between the fresh water usage and sewer discharge for the Auto Bay when
using/not using a recycling system.




Tables 2 + 3 (below) show the maximum number of car washes that can occur in the different
types of wash bay per hour and lists the total peak demand of fresh (mains) water and peak
sewer discharge. Note that these two tables combine the absolute limit of every wash bay
working at 100% maximum capacity for an entire hour.




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