After three years of negotiations, a coalition that includes Palo Alto, Mountain View, Menlo Park and about two dozen other cities is preparing to sign off on a revised deal with its water supplier, the San Francisco Public Utilities Commission. The agreement between the Bay Area Water Supply and Conservation Association, which represents the 26 municipalities, and the SFPUC seeks to take some of the pressure off cities that have not bought their minimally required allotment thanks to conservation efforts and alternate supplies. This includes Mountain View, which has had to pay millions of dollars in penalties over the past 15 years for not meeting the purchase quotas, and which would see some relief in the amended agreement.