Reel McKoi wrote:

It sounds like these abandoned
pools can be a health hazard. Not only because of mosquitoes but
children or pets can fall into them and drown.

Most municipalities require a pool fence with an auto latching gate, but
every year there are about 5-10 drowning fatalities of kids under 5.
Even when the water is not murky and there are adults nearby. Kids are
inquisitive and quick.

Don't know if there are such laws for ponds.

Chip