Click on the USGS buoy link up top the water temperature page, and there's five different line graphs that show water temperature, lake water height, specific conductance, dissolved oxygen, and ph. The USGS buoy is located just beyond the swim line at weirs beach.
The NH DES does the testing for e-coli bacteria, and will post bright orange warning signs along the beach shoreline. Some NH towns will close their public area, while others will leave the choice up to you, the beach goer/swimmer, without closing the beach/water, even though the state has posted e-coli warning signs.
Last summer, 7-acre Corcoran's Pond in Waterville Valley was posted in the sandy beach with two black and yellow e-coli warning signs from the NH DES, and the Town of Waterville Valley closed the pond to swimmers, and closed it to kayaks and paddle boards too. As far as I know, the City of Laconia will not close the water to swimmers when the NH DES posts warning signs for e-coli, and just leaves it up to the individual swimmer/water-goer while the warning signs are posted at the shoreline in the sand.
http://www.des.nh.gov/organization/d...teria_sign.gif .... the NH DES travels all across the state, testing the water at ponds, lakes, public swim pools, and hot tubs, and will post these signs in a conspicuous spot like attached to a 48" wood stake, posted into the sandy shoreline at a public beach, at the water's edge. It's up to the local town, not the state, to make a decision to actually close the area, or to leave the sign in place and let people decide for themselves to swim or not to swim .... that is the question! It always seems more than a little strange to me when these signs are posted, and people including children are choosing to go into the water what with the town lifeguard present ........ who will explain the situation ........yes, that sign is for real ........ but, it is your personal choice ..... to swim or not to swim?
That's New Hampshire for yuh .........ayuh!