Purissima Hills Water District (PHWD), a county water district, provides chloraminated water service to two-thirds of the town of Los Altos Hills, adjacent to the city of Palo Alto in Northern California. With remote tank locations, low population density (6,800 people) and low water demand (1.61MGD), PHWD is constantly challenged to maintain consistent disinfectant residual levels while simultaneously balancing the safe delivery of chemicals to its tank site at an affordable cost. Despite the challenges, PHWD operators take pride in providing consistently high-quality drinking water to the region – recently named the wealthiest town in the United States1 – through continually investing in innovative water quality technologies and outstanding operating practices.

Working together with PSI Water Technologies, Inc. a Cleanwater1 company since 2013, PHWD has successfully implemented numerous projects to address water quality concerns in its distribution system, including adding tank mixers to overcome stratification, aeration and ventilation equipment to remove trihalomethanes (THMs), and sensors and chemical dosing skids for residual control. Most recently, PHWD was introduced to PSI’s Microclor® On-Site Sodium Hypochlorite Generation (OSHG) system, which uses salt and electricity to produce chlorine in the form of sodium hypochlorite, versus using chlorine from gas or liquid bulk hypochlorite.