Testing a pipeline shall be carried out before any backfilling takes place and shall be repeated after backfilling is completed, and should be in accordance with the standard specifications of water and air testing of drains and sewers.
Water Testing of a Pipeline
Before testing, attention should be paid to the following points:
- Inspect pipeline for possible damage during or subsequent to laying.
- Plugs, should be thoroughly checked. Faulty plugs will invalidate test results.
- Close all opening in the line with watertight seals (Test Stoppers) ensuring that it's adequately strutted against movement. i.e. all plugs held firmly in position.
- Ventilating valve should be fixed at the high point of the section.
- Testing time should not exceed the test period as mentioned in the standard (15 minutes).
Testing Procedure
- Fill the line with water, commencing at the low point till you reach a head of 5.0 meter (Testing Pressure) measured at the low point of the line.
- Take care to expel all air from the line.
- Inspect the line for any obvious leak.
- Maintain test pressure (5.0 m) for one hour by topping up with water.
- Maintain test pressure for another 15 minutes (Test measuring time).
- Measure the amount of water required to maintain this pressure for 15 minutes, by adding water to maintain the original level and record the quantity added. This quantity should not exceed 0.07 L/m2 of wetted inner surface.
- The pipeline is considered acceptable if no leakage is visible in the pipes, and if water loss in the water head does not exceed the allowable value (0.07 L/m2) during test time (15 min.).

Air Test
The air test is an alternative to the water test. Pipes can be considered as faulty only in the event of failure under the water test. Test shall be applied as detailed below:

- Inspect pipeline for possible damage during or subsequent to laying.
- Thoroughly check all plugs and equipment. The average drain plug is quite often not airtight and rubber tubing used in connections must be in good condition and not perished.
- Ensure that the ends of the line are adequately strutted against movement with all plugs held firmly in position.
- Pump or blow in air until a pressure of slightly in excess of 4 in. (100mm) water gauge is indicated on the manometer connected to the system.
- Pumping or blowing warms the air so a minute or two should be allowed for this to cool to the pipe temperature.
- If necessary, then reduce the pressure to 4 in. (100mm) water gauge.
- During a further period of 5 minutes the air pressure should not fall below 3 in (75mm) water gauge.