(a) 
Maintenance Holes. The contractor shall construct maintenance holes at the points and of the type shown on the improvement plans. All maintenance holes shall be watertight structures with concentric cones and precast reinforced barrel sections conforming to Standard Drawing No. 13. Maintenance holes shall have a 48-inch interior diameter for all sewers except that 60-inch interior diameter maintenance holes are required for all trunk sewers 21 inches or larger in diameter.
(b) 
Maintenance Hole Bases. Concrete for the base shall be Class 2 concrete. Maintenance hole base shall be cast in place and shall be placed on firm, undisturbed ground. If water or soft soils are present, a minimum of eight inches of three-quarter-inch crushed rock bedding shall be placed. Internal vibrators will be required for consolidation of concrete on all poured maintenance hole bases. An impression ring shall be placed in the “wet” concrete to produce a depression for a precast maintenance hole section. Where possible the pipe will be laid through the maintenance hole and the top broken out to springline after the concrete in the base has set. Precast maintenance hole base is not acceptable without written acceptance by the District and shall not be altered in any way once delivered on site. A CVSan inspector must be notified in advance and must be present when the maintenance hole base is poured. The maintenance hole base shall consist of one continuous concrete pour. Water stops are required for all new maintenance holes.
(c) 
Precast Maintenance Hole Sections. Precast maintenance hole sections, conforming to Section 3209 of this Code, shall be the standard maintenance holes for the District. Joints between concrete maintenance hole sections and other parts including base shall be completely filled with preformed plastic joint material such as Ram-Nek. Cement mortar shall be applied to the inside and outside wall of the joint. Trim mortar smooth for interior and exterior joints. For locations with groundwater, apply external concrete joint tape wrap, Rub’R Nek six inches wide by Henry Company. Maximum allowable distance from the top of cone section to the top of maintenance hole frame shall be 12 inches.
The interior and exterior surfaces of the precast maintenance hole sections shall be coated with a concrete sealant material: Tegraproof, Xypex, bituminous material, or other cement water-proofing material approved by the District.
(d) 
Maintenance Hole Steps. Shall be installed only if specified or directed to by the authorized District representative.
(e) 
Castings. Castings shall conform to the shape, weights and dimensions shown in Standard Drawing No. 11, and Section 3203 of this Code. The frame shall be accurately set to the street grade or ground surface. Covers shall fit snugly and shall not “rock” in the frames. In paved and unpaved areas, unless specified by the authorized District representative, a concrete collar shall be poured around the frame, adjusting ring and cone as shown on Standard Drawing No. 13.
(Added, § 1, Ord. 35, 04-06-1959; amended, § 1, Ord. 52, 08-05-1975; § 2, Ord. 76, 02-12-1985; § 1, Ord. 133, 01-07-2003; § 1, Ord. 138, 07-01-2005; § 1, Ord. 150, 07-01-2009; § 1, Ord. 162, 07-01-2014; § 1, Ord. 169, 05-03-2016; § 1, Ord. 174, 11-07-2017; § 1, Ord. 183, 09-03-2019; § 1, Ord. 204, 05-06-2025)
[1]
Previously 3058.
Particular care must be taken to protect the maintenance hole from damage and to keep rock, dirt and/or debris from getting into the sewer. After the sewer pipe through the maintenance hole has been broken out and channel finished, a false bottom shall be placed over channel whenever construction work is performed at the maintenance hole. A temporary metal plate cover, of adequate strength, close-fitting and well-secured, shall be placed over the maintenance hole opening until the frame and cover are permanently installed, as shown in Standard Drawing No. 22.
(Added, § 1, Ord. 35, 04-06-1959; amended, § 1, Ord. 150, 07-01-2009; § 1, Ord. 162, 07-01-2014; § 1, Ord. 169, 05-03-2016; § 1, Ord. 183, 09-03-2019; § 1, Ord. 204, 05-06-2025)
[1]
Previously 3060.
All sewer maintenance holes shall be vacuum tested prior to backfill. Vacuum test procedures and requirements shall be as follows:
(a) 
After completion of the maintenance hole barrels and prior to grade ring installation, all openings in the maintenance hole are sealed with plugs and a rubber ring “donut” type plug inserted inside the opening of the cone.
(b) 
The vacuum test shall be performed in accordance with Standard Test Method for Concrete Sewer Maintenance Holes by Negative Air Pressure (Vacuum) Test Prior to Backfill, ASTM Designation C 1244-05a. A small vacuum pump shall be attached to a hose connected to the plug and 10 inches mercury (Hg) of vacuum applied. The vacuum line shall be closed and the vacuum pump shut down. The time shall be measured for the vacuum to drop to nine inches mercury. The maintenance hole is acceptable if the time for the vacuum reading to drop from 10 inches Hg to nine inches Hg meets or exceeds the values listed in subsection (c) of this section. The maintenance hole must maintain vacuum such that no greater than one inch Hg of vacuum is lost during the specified test period.
(c) 
The specified test period is as follows:
Maintenance Hole Depth (feet)
Test Period Based On Maintenance Hole Size (seconds)
48-Inch Diameter
60-Inch Diameter
72-Inch Diameter
Up to 8
20
26
33
10
25
33
41
12
30
39
49
14
35
46
57
16
40
52
67
18
45
59
73
20
50
65
81
22
55
72
89
(d) 
Maintenance holes that fail the test shall be patched as required and retested.
(e) 
A vacuum regulator shall be provided on the vacuum pump such that no greater than 10.5 inches Hg can be applied to the maintenance hole during the test. All maintenance holes that do not meet the leakage test or are unsatisfactory from visual inspection shall be repaired or replaced to the satisfaction of the District Inspection Staff.
(Added, § 5, Ord. 119, 06-03-1998; amended, § 1, Ord. 126, 02-01-2000; § 1, Ord. 133, 01-07-2003; § 1, Ord. 138, 07-01-2005; § 1, Ord. 150, 07-01-2009; § 1, Ord. 162, 07-01-2014; § 1, Ord. 169, 05-03-2016; § 1, Ord. 204, 05-06-2025)
[1]
Previously 3094.