[[Image:cloth filtering.jpg|thumb|right|600px|The steps of filtering water through a cloth. Diagram: CARE/CDC Health Initiative, etc. from [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=14&ved=0CDgQFjADOAo&url=http%3A%2F%2Fwww.cdc.gov%2Fsafewater%2Fmanual%2Fsws_manual.pdf&ei=UYI1UOSsLIOviAK2zYFI&usg=AFQjCNGAyphAifOHvfYLoZ4oOxxTDn_c_g&sig2=CbDFQ2mGaKU44X6_m1SsYQ Safe ProjectsSafe Water Systems for theDeveloping World:A Handbook for ImplementingHousehold-Based Water Treatmentand Safe Storage ProjectsEstes.]]]
Straining water through a cloth has been widely used for household water treatment in many cultures for centuries. A common sari cloth is usually used for this in South Asia, for example (photo on right). Straining through a fine cloth can take out guinea-worm, organic matter, and help clear up turbidity. Such cloths are effective in straining out the copepods in the water. These tiny water creatures act as intermediate hosts for the larvae which transmit the disease. Some guinea-worm eradication projects supply a large-diameter drinkingstraw with a filter mesh on one end so thatcopepods are strained out when water is sucked up the straw.
The pore size range in old (laundered) sari cloth is 100–150 μm, but about 20 μm if the cloth is folded four to eight times. The holes allow water to pass but retain particles and pathogens >20 μm. Straining through sari cloth has been shown to be effective in filtering out the plankton to which cholera bacteria may attach themselves, therefore reducing the risk of cholera. This simple method can also filter out many helminths and their eggs and larvae.
* [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CEwQFjAA&url=ftp%3A%2F%2Fftp.wpro.who.int%2Fscratch%2FENH%2FHWTS%2FWHO%2520Final%2FParticipant%2520Manual%2FAppendices%2FParticipant%2520Manual_Appendix%25202_HWTS%2520Fact%2520Sheets_2011-09-05%2F3_Filtration%2FHWTS%2520Fact%2520Sheet_Straining_2011-06.doc&ei=dWDzT-eUBsqe2wWuzLj0Aw&usg=AFQjCNE2W01XfY7H6vgiYqrXUbX5fBvOsw&sig2=w5pcG7VmiOWuptaiv_3BnA ''Household Water Treatment and Safe Storage Fact Sheet: Straining''.] CAWST. Calgary, Alberta, Canada.
* Brikke, François, and Bredero, Maarten. ''[http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CC0QFjAB&url=http%3A%2F%2Fwww.who.int%2Fwater_sanitation_health%2Fhygiene%2Fom%2Flinkingintro.pdf&ei=cwJpT-zaO-OiiQKCst2rBw&usg=AFQjCNEWOQhTgF3a7lzhuw5OA2KmbVGxcA&sig2=Rt2EURUyGVqDcwFg6p0xAw Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff]''. World Health Organization and IRC Water and Sanitation Centre. Geneva, Switzerland 2003.
* [http://www.lboro.ac.uk/well/resources/technical-briefs/58-household-water-treatment-1.pdf 58. Household water treatment I]. WATER AND ENVIRONMENTAL HEALTH AT LONDON AND LOUGHBOROUGH (WELL).