§ 15.01.620. Cleaning and testing sanitary sewer lines.

A.

Cleaning. After the sewer lines have been laid and the trench backfilled, they shall be thoroughly cleaned and tested for leakage and alignment in the presence of the city engineer or the city inspector before acceptance by the owner. Laterals and trunk lines shall be flushed by water to remove all foreign material. Wastewater and debris shall not be permitted to enter sewer lines in service, but shall be removed at the lowest manhole of the excavation. The scouring action shall be accomplished by hydraulic or jet cleaning. Other methods may be used upon approval of the city engineer. After the lines have been thoroughly cleaned, they shall be tested between all manholes for displacement.

B.

Displacement test. The displacement test shall be supervised a conducted by the city engineer or the city inspector and shall consist of both of the following: (1) A light will be flashed between the manholes, or if the manholes have not as yet been constructed, between the locations of the manholes, by means of a flashlight or by reflecting sunlight with a mirror. If the illuminated interior of the pipe shows broken, misaligned or displaced pipe, or other defects, the defects designated by the city engineer shall be remedied by the contractor; (2) After sub base has been placed and compacted, prior to asphalt placement, the sewer line will be televised by the contractor. The contractor will supply and provide the city with a tape copy of the inspection along with a schematic plan identifying key locations on the video. The initial inspection shall be provided at no cost to the city. If the pipeline is found to be unacceptable, the problem shall be corrected by the contractor and re-televised. Television inspection must be scheduled at least one week in advance of date inspection is requested.

C.

Exfiltration test. As required by the public works director or city engineer, each section of the sewer shall be tested between adjacent manholes by closing the lower end of the sewer to be tested and the inlet sewer of the upper manhole with stoppers. The pipe and manhole shall be filled with water to a point approximately four feet above the invert of the sewer at the center of the upper manhole or to four feet above the natural groundwater level, whichever is higher. All manhole and pipe sections shall also be required to pass an air test as described herein.

The maximum allowable exfiltration shall not exceed one hundred fifty gallons per inch diameter per mile per twenty-four hours for all installed sewer pipe.

A test may include an air pressure test at 4.0 PSI between adjacent manholes.

If the leakage from the sewer as shown by the test is in excess of the maximum allowable, the contractor will make the necessary corrections to reduce the exfiltration to within permissive limits.

Where the difference in elevation between inverts of adjacent manholes exceeds ten feet, the exfiltration leakage test will be modified as directed by the city engineer.

House surface laterals shall be considered part of the main line sewer to which they are connected and shall be tested with the main line sewer.

D.

Infiltration test. In addition to the exfiltration test, the newly laid sewer system shall also comply with the following infiltration requirements. Infiltration tests shall be conducted by placing an approved calibrated V-notch weir in the line just above the next lower manhole and plugging the line just above the next higher manhole. Sufficient time shall be allowed for the water level behind the weir to stabilize before reading. Dislodge any foreign material obstructing the weir before reading. Take successive readings until consistent results are obtained.

Whenever the rate of infiltration is found to exceed the maximum, conduct electronic or photographic visual inspection of the interior of the pipeline. Make repairs and continue to test the conduit until it is within specified limits prior to proceeding with further construction. Make repairs at all manholes to exclude all infiltration occurring, whether or not they are within specified limits.

The maximum allowable infiltration for any section of the system shall be as follows, subject to the limitations described hereafter:

I = 150 gallons/mile/inch/diameter/day.

Upon completion of all sectionalized testing, the total project infiltration of the newly constructed system shall be measured and recorded. This value shall be limited to one hundred twenty-five gallons/mile/inch/diameter/day. Make repairs and continue to test for total project infiltration until it is within this specified limit.

(Ord. No. 2007-07-31, §§ 6.11—6.11.4, 7-10-2007; Ord. No. 2010-11-24, § 2, 11-23-2010; Ord. No. 2012-05-15, § 1, 5-8-2012)