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Re: drywell constructionFrom: info@builderswebsource.com
Category: Drainage/Waterproofing
Remote Name: 63.198.181.43
Date: 11 Jun 2002
Time: 12:58 AM
CommentsBefore constructing a drywell for discharge of anything other than storm runoff, you must contact your local jurisdiction to determine if graywater drywells are permitted. Furthermore, as to distance from the foundation, this depends on the percolation of the soil and the volume of water expected. The simple answer is to put it downhill of your foundation, at least 20-50 feet away or great. The following tips are recited from the Arizona Department of Environmental Quality regarding drywell construction. Regulations in your state may vary. "Drywells should be installed to dispose of only stormwater and urbansurface run-off as defined in this guidance. Other discharges to a drywell may trigger requirements for regulation as an underground injection wellunder state and federal regulations. 2. No drywell should be installed closer than 100 feet from any water well. Drywells should be installed as far as possible, but no closer than 20 feet, from underground storage tanks or fuel loading areas. 3.Installation of drywells where hazardous or toxic materials are used, handled, stored, loaded or treated, or where a spill of such materials could drain into the drywell system is not recommended. If it is necessary to install a drywell in such areas, an Aquifer Protection Permit (APP) is required. If a permit is necessary, an engineered design such as the Envibro system or equivalent, which utilizes interceptors, sumps orother devices to remove, intercept and collect pollutants, may be necessary to meet the required Best Available Demonstrated Control Technology (BADCT). 4.Drywells should be at least 10 feet above the water table. In the event perched water tables are encountered, drywell systems may be constructed by an installer licensed by the Arizona Department of WaterResources (ADWR) as long as the perching formation is sealed per ADWR requirements. 5. Drywell installers shall meet the licensing requirements of the State Registrar of Contractors and the Arizona Department of Water Resources. 6. If the above conditions can not be met, please consult with ADEQ. 7. During construction, drywell inlets (including any remote inlets or connected catch basins) should be sealed with two layers of U.V. protected geotextile fabric to prevent sediments from entering the drywells until paving and landscaping are complete. 8. A solid manhole cover should be installed on the drywell to insure flow is through the interceptor inlet only. The cover should be bolted in at least two locations and marked in raised cast letters "stormwater."
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