Section 410IAC6-10.1-65. Construction of sewers

   (a) Sewers beginning three (3) feet outside the foundation walls of buildings shall be constructed of piping that meets the minimum requirements of section 75(a)(1) or 75(a)(2) of this rule.

  (b) Sewers serving individual units may connect to the main sewer by wye fittings. Sewers serving more than one (1) unit must connect to the main sewer at a manhole.

  (c) Sewers shall be laid to a uniform grade and at a slope equal to or greater than the minimum slopes shown in Table IV as follows and may not be increased in size for the sole purpose of reducing the required slope:

Table IV – Minimum Slope for Sewers
Sewer Size	Minimum Slope in Feet per 100 Feet*
4 inch diameter (building sewer only)	1.33
6 inch diameter	0.61
8 inch diameter	0.40
10 inch diameter	0.28
12 inch diameter	0.22
15 inch diameter	0.15
16 inch diameter	0.14
18 inch diameter	0.12
21 inch diameter	0.10
24 inch diameter	0.08
*Based on the Hazen-Williams formula using C = 140.

  (d) No outside building sewer shall be less than four (4) inches in diameter. Minimum sewer diameters will vary upward from four (4) inches according to use. Because of slope, cleaning, and maintenance problems, installation of four (4) inch sewers is unacceptable except where they can adequately serve a building or facility having very low anticipated sewage flows. Sewers shall be adequately sized to carry average and intermittent peak flows. Soil, waste, vent, and drain piping inside the building shall comply with the Indiana Plumbing Code (675 IAC 16).

  (e) Adequate sewer bedding shall be provided. All sewers shall be buried with at least two (2) feet of cover to protect them from freezing. Force mains must be buried deep enough to prevent freezing unless the lift station and force main can be designed such that the force main will drain completely.

  (f) Sewers proposed under driveways, parking slabs, or other heavily loaded areas, shall be adequately constructed to prevent damage or breaking.

  (g) Manholes must be installed at the end of each line, at all changes in grade, size, or alignment, at all intersections, and at intervals not greater than four hundred (400) feet for sewers fifteen (15) inches diameter or less. Intervals not greater than five hundred (500) feet are allowed for sewers eighteen (18) inches or greater in diameter.

  (h) A drop manhole should be installed where a sewer enters the manhole twenty-four (24) inches or more above the manhole invert. The outside drop connection constructed with a drop manhole should be encased in concrete.

  (i) The minimum acceptable diameter for manholes is forty-eight (48) inches. The access opening into the manhole must be at least twenty-two (22) inches in diameter.

  (j) Cleanouts may be substituted for manholes on short sewer runs. Cleanouts must:

(1) be the same diameter as the sewer they are to serve; and

(2) extend to grade.

A cleanout may be installed at the terminus of a sewer provided that a manhole is within three hundred (300) feet of the terminus. (Indiana State Department of Health; 410 IAC 6-10.1-65; filed Oct 19, 2012, 2:07 p.m.: 20121114-IR-410120157FRA)