The standard drywell is the Maxwell IV or equal. The standard drywell system shall include an Interceptor Well upstream of any drywell(s).
Drywells will be offset a nominal distance of 20 feet from any surface inlet. When a drywell is constructed in conjunction with a surface inlet, the diameter of the connecting pipe from the interceptor well to the drywell shall be a maximum of 4 inches.
Drywells constructed in a landscaped area shall have a rim elevation 2.0 inches above the finished elevation. Design of drywells in detention basins will not be allowed. Drywells are intended for nuisance water disposal, not storm water disposal.
Drywells will remain sealed until all paving or landscaping is completed (or until new grass is stable) to prevent unnecessary sediment from being deposited in the drywell.
Drywells will have a minimum settling basin depth of 25 feet, a 4 foot inside diameter, 30 inch bolt down grates and 6 inch drainage components. Drywell dimensions may be varied, subject to the approval of the City Engineer, if the settling volume is 250 cubic feet or greater.
Drywells will be spaced a minimum of 75 feet center to center.
The minimum distance between a drywell and a waterwell shall be 300 feet.
Drywell design shall be in accordance with City Stds. D-1.1 and D-1.2
a. A Soils Engineer or an Engineering Geologist shall perform percolation tests on each drywell installed to verify its capability to dispose of the anticipated inflows.
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