Water tightness of the house drains are key factor for their efficiency. To check the water tightness, house drains are tested after they are laid. These tests are done in sections between successive inspection chambers and the vertical pipes are tested in groups, each group having one common inspection chamber.
1) Air Test:
In this test, the pipe is kept plugged both at lower and upper ends and air is forced into the pipe with the help of a pump. All the joints of the drain are coated with soapy solution. If any joint is leaking, it will form bubbles at the joints. The joint is then marked and the leakage is rectified.
2) Water Test:
In this test the drain is plugged at the lower inspection chamber and water is filled in the pipe to cause a pressure equivalent to a head of 1.5m. If there is no leakage in the drainage system then there should not be any visible drop in the water level within 10 minutes.
3) Smoke Test:
This test is carried out to detect the leakage of rain water pipes and other vertical waste pipes. In this test the smoke is forced into the pipe with the help of blowers. In case of any leakage, it may be sighted by smell or vision of the smoke emitting through the joints.
So these are some easy and simple tests which should be done before the house drains are declared to be ready to use.