(4) A sanitary sewer shall be installed with straight alignment between manholes.
(5) A manhole shall be installed at the end of each sewer line, at all changes in grade, size,
or alignment, at all intersections, and at distances of not more than 400 feet along sewers.
A drop pipe shall be provided for a sanitary sewer entering a manhole at an elevation 24
inches or more above the manhole invert. A cleanout may be substituted for a manhole at
the end of a lateral not more than 150 feet in length. The flow channel through a manhole
shall conform in slope and shape to that of the sanitary sewers.
(6) A sanitary sewer shall be designed to prevent damage from superimposed loads.
Proper allowance for loads on the sanitary sewer shall consider the width and depth of
trench. When standard strength sewer pipe is not sufficient, extra strength pipe or special
construction technique shall be used.
(7) Leakage tests shall be specified by the engineer for sewer construction. Leakage
outward or inward shall not exceed 200 gallons per inch of pipe diameter per mile per day.
(8) There shall be no connection between a mobile home park or seasonal mobile home
park water system and a sanitary sewer. A sanitary sewer or individual sewer service line
shall not be laid within 10 feet horizontally of a waterline.
(9) Where a sanitary sewer line crosses a waterline, there shall be a minimum of 12 inches
of clear vertical isolation distance between the two. Where conditions require less vertical
isolation, the sanitary sewer line shall be encased in concrete for 5 feet each side of the
crossing. One full length of waterline shall be centered over the sanitary sewer crossing.
(10) A mobile home sanitary sewer service connection shall incorporate a p-trap installed
at a sufficient depth to prevent freezing. The p-trap and riser pipe shall be constructed of
cast iron or schedule 40 plastic pipe. The riser shall terminate not less than 4 inches above
final grade and shall be located not closer than 5 feet from a water service riser. A riser
shall be securely capped when not in use.
(11) A mobile home park or seasonal mobile home park shall be served by a common
sanitary sewer system.
(12) A site in a mobile home park or seasonal mobile home park shall be provided with
an individual sewer connection.
History: 1980 AACS; 1984 AACS.
R 325.3332 Design of sewage treatment facilities.
Rule 32. (1) When a mobile home park or seasonal mobile home park sanitary sewer
system is not connected to a municipally owned sanitary sewer system, a sanitary sewerage
system approved by the health department shall be provided.
(2) The publication entitled "Recommended Standards for Sewage Works," 1978 edition,
as published by the Great Lakes-upper Mississippi river board of state sanitary engineers,
shall be used as a standard for the design of sewage treatment facilities. These standards
are available for inspection at the health department offices in Lansing and Escanaba and
are available for purchase at the Michigan Department of Public Health, P.O. Box 30035,
Lansing, Michigan 48909, and from the Health Education Service, P.O. Box 7283, Albany,
New York 12224, at a cost of $1.75.
History: 1980 AACS; 1984 AACS.
Page 4
Courtesy of Michigan Administrative Rules