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Section 38 – Sewer and Storm Drain Construction

38-10.02.B Hydrostatic Test for Leakage - Sewer

A section of line shall be prepared for testing by plugging the upper side of the downstream

manhole and all openings in the upstream manhole except the downstream opening. Care shall

be exercised in installing plugs to avoid interrupting service to existing sewer or storm drain

services. Where grades are slight, two (2) or more sections between manholes may be tested

at once. Where grades are steep and excessive heads would result by testing from one

manhole to another, test tees, the same size as the main, shall be installed at intermediate

points so the maximum head on any section under test shall not exceed twelve feet (12’).

A section of line prepared as above shall be tested by filling with water to an elevation five

feet (5’) above the top of pipe at the upstream end of the test section, or five feet (5’) above the

existing ground water elevation, whichever is greater. The water shall be introduced into the

test section at least four (4) hours in advance of the test period to allow the pipe and joint

material to become saturated with water. The water level should then again be brought to the

five-foot (5’) mark. At the beginning of the test, the elevation of the water in the upper manhole

shall be carefully measured from a point on the manhole rim or test tee. After a period of four

(4) hours, or less with the approval of the Agency, the water elevation shall be measured from

the same point on the manhole rim and the loss of water during the test period calculated. If

this calculation is difficult, enough water shall be measured into the upper manhole to restore

the water to the level existing at the beginning of the test, and the amount added taken as the

Unless otherwise specified in the Special Provisions, the allowable leakage in the test

section shall not exceed fifty (50) gallons per mile per day per inch diameter of pipe tested at

the five-foot (5’) test head. If it is necessary or desirable to increase the test head above five

feet (5’), the allowable leakage will be increased at the daily rate of fifty (50) gallons for each

foot of increase in head.

Test sections showing leakage in excess of that allowed shall be repaired or reconstructed

as necessary to reduce the leakage to that specified above.

Water used in testing shall be disposed as directed by Agency. No testing water shall be

allowed to enter the existing sanitary sewer system.

38-10.02.C Air Test for Leakage - Storm Drain

Only lines tested after backfilling to final grade will be considered for acceptability.

However, this test may also be used by the installer as a presumptive test to determine the

condition of the line prior to backfilling.

The Contractor shall furnish all the necessary equipment and be responsible for conducting

all low-pressure air tests. In addition, the Contractor is responsible for any necessary repair

work on sections that do not pass the test. No sealant shall be used in any newly installed

storm drain without the prior approval of the Agency. Using sealant in a storm drain is not the

equivalent of a sound storm drain pipe. Proper structural repair work may be required by the

The Agency will witness all low-pressure air tests and verify the accuracy and acceptability

of the equipment utilized.

38-10.02.C.(1) Plug Restraint

Restraints must be provided for plug to prevent blowouts of the plug. As an example of the

hazard, a force of two hundred fifty (250) pounds is exerted on an eight-inch (8”) plug by an

internal pipe pressure of five pounds per square inch, gauge (5 psig), and a force of two

thousand two hundred fifty (2,250) pounds is exerted on a twenty-four-inch (24”) plug by an

internal pressure of five pounds per square inch, gauge (5 psig). Sudden expulsion of a poorly

installed plug or of a plug that is partially deflated before the pipe pressure is released can be

very dangerous. For this reason, it is recommended that every plug be positively braced

against the manhole walls, and that no one be allowed in the manhole adjoining a line being