1. A constant-head test assembly is as given in below figure.
2. Select a representative soil mass of about 2.5 kg properly mixed.
3. Fill the soil into the mould and compact it to the required dry density by making use of a suitable compacting device.
4. Set the assembly as shown in figure after saturating the porous stones.
5. The water supply is properly adjusted to maintain constant head.
6. Open the valve and saturate the sample by allowing water to flow through for a sufficiently long time to remove all air-bubbles.
7. When the whole setup is ready for the test, open the valve, allow the water to flow through the sample collect water in a graduated jar starting simultaneously a stopwatch. Note the time to collect a certain quantity of water Q.
8. Repeat the test three times and determine the average of Q for the same time intervalt.
9. Measure the head h, length of sample L, and calculate the cross sectional area A of the sample.
10. Calculate k by making use of equation.