Question

explain why it is advisable to get the soil tested for its percolation rate before installing a rainwater harvesting system​

Answer 1

In a well-functioning greywater system, greywater soaks into the ground without pooling or running off. In general, clayey soils drain very slowly, while sandy or gravelly soils drain quickly. A home percolation test is a simple way to measure how quickly your soil drains and to determine how much area you need to infiltrate the greywater. Professional percolation tests, required for septic leach fields, are expensive, and unnecessary for a small greywater system. Many greywater codes use a soil type chart to predict drainage rates instead of percolation rate data.

Greywater percolation tests should be conducted at the depth of discharge, ideally less than one foot.