The Clay pot biological filter was tested under controlled conditions at LSRDA and in village homes in 2003-4 in Pakistan. The Delagua portable water testing lab was used which is designed by Oxfam in conjunction with Surrey University for testing drinking water quality in the field.

It incubates ecoli for counting by eye (ecoli are a good indicator of water quality in rural conditions in a developing country).

Results were very good which was not a surprise. This is because the filter produces the same controlled environment, as the excellent bio-sand filter promoted by CAWST and so the way the filter works and its performance are similar.

Information on its performance can be found on the internet through the CAWST website. and by surfing for info on biosand filters.

Before filtration 320 ecoli in 100ml of raw drinking water (ecoli are a good indicator of water quality).

After being filtered by the filter above, typically only one ecoli is counted in 100ml (This water is safe to drink).