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D.C. Municipal Regulations (Last Updated: September 13, 2017) |
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Title 21. WATER AND SANITATION |
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Chapter 21-18. WELL CONSTRUCTION, MAINTENANCE, AND ABANDONMENT STANDARDS |
Section 21-1817. WELL CONSTRUCTION REQUIREMENTS: FILTER PACK IN WELL
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1817.1Except for a pre-packed well, a filter pack shall be placed in the well annulus surrounding the well screen.
1817.2A filter pack shall extend a minimum of two feet (2 ft.), but no further than three feet (3 ft.) above the well screen.
1817.3A filter pack shall be comprised of sand or gravel that has been washed with water and is free of clay, silt, and organic material.
1817.4A filter pack shall not contain iron or manganese in concentrations greater than that in the ground when the well is installed or adversely affect the quality of water withdrawn from the well or the groundwater that comes into contact with the filter pack.
1817.5A filter pack material stored at the drilling site shall be stored on a clean surface or in a clean container to prevent any on-site contaminants from mixing with the filter pack materials.
1817.6A filter pack shall be inserted by one of the following methods:
(a)By placing the filter pack down the annulus;
(b)By placing a water-filter pack mix down the annulus; or
(c)By using a tremie pipe to insert a water-filter pack mix at the bottom of the annulus and slowly raising the tremie pipe.
1817.7A pre-packed well screen shall:
(a)Be used in accordance with the manufacturer’s specifications and recommendations;
(b)Not contain materials that may alter groundwater chemistry or pose a hazard to the environment or public health and safety; and
(c)Be pre-approved in writing by the Department prior to installation.
1817.8The well filter pack material shall not hydraulically connect otherwise confined aquifers, without prior written approval from the Department.