Khmer Times/Maddy Crowell

Browse any online expat or tourist forum where people ask whether the tap water in Phnom Penh is safe to drink and you will likely find an adamant “No!” But according to water sanitation experts, these forums are wrong. Phnom Penh has some of the safest drinking water in the world, better than London or Tokyo – in theory.

“We can drink water directly from the tap. I already tested the water at the office; there is no e. coli in it,” said Ratana Chai, water quality testing trainer for Third World Service. “For me, I think it’s safe to drink the tap water in every household. The amount of chlorine will prevent recontamination in 48 hours.”

Water in Phnom Penh comes primarily from the Mekong and Tonle Sap rivers, and is sourced at a water sanitation plant in Sangkat Srah Chak, which was established by the Phnom Penh Water Sanitation Authority (PPWSA) in 1993.

read more http://www.khmertimeskh.com/news/23533/city---s-tap-water-gets-thumbs-up/

"But the mainline pipes that connect to the filtration center only extend so far – most households have their own piping system, and contamination depends on their quality."

Bingo!!