November 24, 2017

Division Three - Standards for Sanitary Sewers - Chapter V. Standards for Separation of Water and Sewer Lines


Chapter V. Standards for Separation of Water and Sewer Lines

Sec. 305-1 General

This document sets forth the construction criteria for the installation of water mains and sewer lines to prevent contamination of the public water supplies from nearby sanitary sewers.

305-1.01 The "California Waterworks Standards" sets forth the minimum separation requirements for water mains and sewer lines. These Standards, contained in Section 64630, Title 22, California Administrative Code, specify:

(a) Parallel Construction: The horizontal distance between pressure water mains and sewer lines shall be at least 10 feet.

(b) Perpendicular Construction (Crossing): Pressure water mains shall be at least one foot above sanitary sewer lines where these lines must cross.

(c) Separation distances specified in (a) above shall be measured from the nearest edges of the facilities.

(d) Common Trench: Water mains and sewer lines must not be installed in the same trench.

(e) Where steel casings or tunnels are used for the passage of water and sewer lines under railroad tracks, highways or other structures, the same shall be specially designed to eliminate any hazard of contamination to the water system.

Sec. 305-2 Exceptions to Basic Separation Standards

Local conditions, such as available space, limited slope, existing structures, etc., may create a situation where there is NO ALTERNATIVE but to install water mains or sewer lines at a distance less than that required by the Basic Separation Standards. In such cases, alternative construction criteria as specified in Section 305-4 should be followed, subject to the special provisions in Section 305-3.

Water mains and sewers of 24 inches in diameter or greater may create special hazards because of the large volumes of flow. Therefore, installations of water mains and sewer lines 24 inches in diameter or larger should be reviewed and approved by the health agency prior to construction.

Sec. 305-3 Special Provisions

305-3.01 The Basic Separation Standards are applicable under normal conditions for sewage collection lines and water distribution mains. More stringent requirements may be necessary if conditions, such as, high groundwater exist.

305-3.02 Sewer lines shall not be installed within 25 feet horizontally of a low head (5 psi or less pressure) water main.

305-3.03 New water mains and sewers shall be pressure tested where the conduits are located ten feet apart or less.

305-3.04 In the installation of water mains or sewer lines, measures should be taken to prevent or minimize disturbances of the existing line. Disturbance of the supporting base of this line could eventually result in failure of this existing pipeline.

305-3.05 Special consideration shall be given to the selection of pipe materials if corrosive conditions are likely to exist. These conditions may be due to soil type and/or the nature of the fluid conveyed in the conduit, such as a septic sewage which produces corrosive hydrogen sulfide.

305-3.06 Sewer Force Mains

    1. Sewer force mains shall not be installed within ten feet (horizontally) of a water main.
    2. When a sewer force main must cross a water line, the crossing should be as close as practical to the perpendicular. The sewer force main should be at least one foot below the water line.
    3. When a new sewer force main crosses under an existing water main, all portions of the sewer force main within ten feet (horizontally) of the water main shall be enclosed in a continuous sleeve.
    4. When a new water main crosses over an existing sewer force main, the water main shall be constructed of pipe materials with a minimum rated working pressure of 200 psi or equivalent pressure rating.
    5. Force mains greater than 1000 feet shall have pressure cleanouts every 600 feet.

Sec. 305-4 Alternate Criteria for Construction

The construction criteria for sewer lines or water mains where the Basic Separation Standards cannot be attained are shown on Plate Nos. S-9 and S-10. There are two situations encountered:

Case 1: New sewer line -- new or existing water main.

Case 2: New water main -- existing sewer line.

For Case 1, the alternate construction criteria apply to the sewer line.

For Case 2, the alternate construction criteria may apply to either or both the water main and sewer line.

The construction criteria should apply to the house laterals that cross ABOVE a pressure water main but not to those house laterals that cross BELOW a pressure water main.

305-4.01 Case 1: New Sewer Being Installed (Plate Nos. S-9 and S-10)

Special Construction Required for Sewer 

Zone A. Sewer lines parallel to water mains shall not be permitted in this zone without approval from the responsible health agency and water supplier. 

Zone B. A sewer line placed parallel to a water line shall be constructed of:

  1. Extra strength vitrified clay pipe with compression joints.
  2. Plastic sewer pipe with rubber ring joints (per ASTM D3034) or equivalent.150
  3. Cast or ductile iron pipe with compression joints.

Zone C. A sewer line crossing a water main shall be constructed of:

  1. Ductile iron pipe with hot dip bituminous coating and mechanical joints.
  2. A continuous section of Class 200 (DR 14 per AWWA C900) plastic pipe or equivalent, centered over the pipe being crossed.
  3. Any sewer pipe within a continuous sleeve.

Zone D. A sewer line crossing a water main shall be constructed of:

  1. A continuous section of ductile iron pipe with hot dip bituminous coating.
  2. A continuous section of Class 200 (DR 14 PER AWWA C900) plastic pipe or equivalent centered on the pipe being crossed.
  3. Any sewer pipe within a continuous sleeve.
  4. Any sewer pipe separated by a ten-foot by tenfoot, four-inch-thick reinforced concrete slab.

305-4.02 Case 2: New Water Mains Being Installed (Plates S-9 & 10)

Zone A. No water mains parallel to sewers shall be constructed without approval from the health agency.

Zone B. If the sewer paralleling the water main does not meet the Case 1, Zone B, requirements, the water main shall be constructed of:

    1. Ductile iron pipe with hot dip bituminous coating.
    2. Dipped and wrapped one-fourth-inch thick welded steel pipe.
    3. Class 200 pressure rated plastic water pipe (DR14 per AWWA C900) or equivalent.
    4. Reinforced concrete pressure pipe, steel cylinder type, per AWWA (C300-74 or C301-79 or C303-70).

Zone C. If the sewer crossing the water main does not meet the Case 1, Zone C, requirements, the water main shall have no joints in Zone C and be constructed of:

  1. Ductile iron pipe with hot dip bituminous coating.
  2. Dipped and wrapped one-fourth-inch-thick welded steel pipe.
  3. Class 200 pressure rated plastic water pipe (DR14 per AWWA C900) or equivalent.
  4. Reinforced concrete pressure pipe, steel cylinder type, per AWWA (C300-74 or C301-79 or C303-70).

Zone D. If the sewer crossing the water main does not meet the requirements for Zone D, Case 1, the water main shall have no joints within four (4) feet from either side of the sewer and shall be constructed of:

  1. Ductile iron pipe with hot dip bituminous coating.
  2. Dipped and wrapped one-fourth (1/4) inch thick welded steel pipe.
  3. Class 200 pressure rated plastic water pipe (Dr 14 per AWWA C900) or equivalent.
  4. Reinforced concrete pressure pipe, steel cylinder type, per AWWA (C300-74 or C301-79 or C303-70).

Sec. 305-5 Notes and Definitions

305-5.01 HEALTH AGENCY - The Department of Health Services. For those water systems supplying fewer than 15 service connections, the local health officer may act for the Department of Health Services.

305-5.02 WATER SUPPLIER - "Person operating a public water system" or "supplier of water" means any person who owns or operates a public water system

305-5.03 LOW HEAD WATER MAIN - Any water main which has a pressure of five psi or less at any time at any point in the main.

305-5.04 DIMENSIONS are from outside of water maim to outside of sewer line or manhole.

305-5.05 COMPRESSION JOINT - A push-on joint that seals by means of the compression of a rubber ring or gasket between the pipe and a bell or coupling.

305-5.06 MECHANICAL JOINTS - Bolted joints.

305-5.07 RATED WORKING WATER PRESSURE OR PRESSURE CLASS - A pipe classification system based upon internal working pressure of the fluid in the pipe, type of pipe material, and the thickness of the pipe wall.

305-5.08 FUSED JOINT - The jointing of sections of pipe using thermal or chemical bonding processes.

305-5.09 SLEEVE - A protective type of steel with a wall thickness of not less than one-fourth inch into which a pipe is inserted.

305-5.10 GROUNDWATER - Subsurface water found in the saturation zone.

305-5.11 HOUSE LATERAL - A sewer connecting the building drain and the main sewer line.

Location

Public Services Building
2700 M Street, Suite 570
Bakersfield, CA 93301-2370
map 

Phone: 661-862-5100 
FAX: 661-862-5101 
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