Massachusetts Regulations - 310 CMR 22.22 (13) (D)
"(d) The public water system is responsible to ensure that each reduced pressure backflow preventer will be inspected semiannually in accordance with the public water system's approved cross connection program plan, as provided for in 310 CMR 22.22(3)(b). If the supply is used less than six months of the year, these devices shall be inspected and tested once each year. Each double check valve assembly shall be tested annually. Pressure type vacuum breakers should be tested at least annually by the owner of the device.Each test shall be conducted by a Certified Backflow Prevention Device Tester."
Fines and Penalties for Non-Compliance
(16)Enforcement.
(a) Whoever maintains a cross connection in violation of M.G.L. c. 111, ยง 160A, shall be:
1. punished by a fine of not more than $25,000 for each day such violation occurs or continues, or by imprisonment for not more than one year, or both such fine and imprisonment, or
2. subject to a civil penalty not to exceed $25,000 per day for each day that such violation occurs or continues.
The Full version of the Regulations can be found here....