The city of Boston and most surrounding communities are under boil water orders following a water main break in Weston.
Boston gets it water from the Quabbin Reservoir in central Massachusetts. It goes to a treatment plant in Marlborough at the I-495 belt and then gets piped into Boston.
When the water main broke in in Weston, MWRA officials didn't want to lose water pressure, so they drew water from the Chestnut Hill Reservoir. That water is untreated pond water, fine for flushing toilets but risky for drinking.
Initially 38 cities and towns served by MWRA in Metro Boston were under the boil order, but some were removed from the list after they switched from MWRA water to local water sources. Cambridge has its own water supply including a water treatment plant at Fresh Pond, so it was insulated from the problem, and there was no boil order for Cambridge.
These 31 cities and towns are still under boil orders:
Lynnfield Water District
All the towns around Cambridge on on the list: Boston, Brookline, Newton, Watertown, Belmont, Arlington, and Somerville. So Cambridge has become an island of clean tap water.
And what do you do if you are under boil orders? In theory you are supposed to boil your water before drinking it or using it for cooking. In practice you run out and buy bottled water, and that led to some fistfights at a BJ's Wholesale Club in Revere.
My advice to those under boil orders who can't find bottled water: buy beer for home consumption or come into Cambridge for a meal at one of our many great restaurants. This Sunday afternoon Cambridge is holding Mayfair on the streets in Harvard Square.
MWRA hopes not to have to tap the Chestnut Hill Reservoir again. It has rerouted the water supply and is working feverishly to fix the leak. At one point, water from the leak was flowing into the Charles River at the rate of 8 million gallons of water an hour. That is one big leak.