The British pint is about 20% larger than the American pint since the two systems are not compatible. Almost all other countries have standardized on the metric system, so the size of what may be called a pint varies depending on local custom.
It is usually measured by the depth (in mm) of the water layer that can enter the soil in one hour. An infiltration rate of 15 mm/hour means that a water layer of 15 mm on the soil surface, will take one hour to infiltrate. In dry soil, water infiltrates rapidly.
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. How to do a home soil percolation test: Step 1. Dig a 6â³-12â³ deep hole in your future greywater infiltration zone. Step 2. Place a ruler (or stick marked in inches) in the bottom of the hole. The measuring device should reach the top of the hole. Step 3. Fill the hole with water several times to saturate the soil.