1. Sea water percolates down through the rocks.

2. Rainwater percolates down through the rock.

3. Sanitary waste from toilets, sinks, and washing machines enters the Cesspool and percolates out.

4. These drains also provide a source of air which percolates up through the bed, keeping it aerobic.

5. 30 Occasional evidence of this percolates through into the newspapers and, now and again, the law reports.