Great to know! I can personally attest that boiling water of unknown provenance (even in cities/small towns) is definitely a good idea... I've had Giarda twice from drinking contaminated water (rain/tank water that I thought was safe) and I can say that both times were extremely unpleasant.

If you need further reason (and you're in a 3rd world country): http://en.wikipedia.org/wiki/Cholera

'infected patients may die within three hours if medical treatment is not provided'... Scary indeed.