Why do you think that the USA & Canada & England abstained from voting for the human right to have safe & clean water to drink?

In doing some internet research on water, I discovered that the UN held a vote on 07/20/10 to affirm that humans have a right to safe & clean water to drink, & sanitation – a right that is essential to even the most minimal life style. The vote was overwhelmingly passed (no countries voted against establishing this right), but the USA, & Canada, & England, abstained from voting FOR this right. My question is, WHY? Why would such strong countries deliberately not vote for something so fundamental?