Walkerton's E. coli drinking water scandal, which killed seven people and made thousands sick in the town exactly a decade ago, has forced Ontario into the vanguard of tapwater safety.

The head of the Canadian Environmental Law Association says supervision had deteriorated before the May 2000 outbreak. But now, Theresa McClenaghan says, Ontario has a very good system. 

Now untrained operators aren't allowed to run water systems, as those in charge in Walkerton and in many other communities did before the tragedy.

No longer does Ontario's Environment Ministry inspect water systems on a haphazard basis and just ask for problems to be corrected.

Quebec has mirrored Ontario's approach, B.C. has expressed interest, while other provinces have put some legislation in place. But there are still no mandatory federal standards.

Ontario is still a work in progress, with source and watershed protection plans that factor in the complexities of agricultural, industrial and development pressures won't be implemented until 2012.

There are about 435 drinking water advisories currently in effect in Ontario, warning people about unsafe conditions.