Overview

The North Penn Water Authority (NPWA) provides potable water to approximately 34,000 customers, primarily in central and northern Montgomery County, PA. The customers are supplied water from the Forest Park Water Treatment Plant with a total capacity of 40 MGD, which draws water from the North Branch Neshaminy Creek, and from 17 groundwater wells with a total capacity of 6.5 MGD. NPWA has two water systems; the Main System and the Sellersville System. The Hillcrest Tank is located in the Main System.

The Main System is divided into multiple pressure zones. The Landsdale pressure Zone is the largest, containing 8 water storage tanks. Built in 1948, the existing 1.25 MG (Million Gallon) Hillcrest standpipe (70 foot high) required significant rehabilitation. An engineering study evaluated the standpipe’s current-day purpose and operational concerns with regard to water quality, pressure, and fire protection. Following the results of an engineering study, we designed, permitted, and provided engineering services during construction for a new 250,000-gallon elevated water spheroid tank on the existing site, and removal of the existing standpipe.

On the Hillcrest Tank site is the Hillcrest Booster Pump Station (BPS). The Hillcrest BPS provides water to a high-pressure zone. This high-pressure zone is a closed system (without a tank). The Hillcrest BPS provides water through two 200 gpm (gallons per minute) pumps controlled by variable frequency drives (VFD). The VFD’s allow the pump flow rate to vary to meet the system water and pressure demands. Because it is a closed system without a tank, the pumps must run continuously to maintain flow and pressure. The Hillcrest BPS also contains a 1,525 gpm fire pump.

The new 250,000 gallon Hillcrest tank is a spheroid style that is 130 feet tall. The height of the new tank will allow it to supply the high-pressure zone via gravity. Therefore the pumps will not have to run continuously, reducing operational costs. The pumps will turn on at low water level in the tank and turn off at a high water level in the tank.
Replacing the old standpipe with an elevated tank nearly twice as high provides more useable gallons of water per foot, thereby reducing water age and increasing water quality. The tank allows gravity water supply rather than constant reliance on mechanical pumps.

During permitting, we provided photographic renderings to NPWA so residents could visualize the new tank’s height, shape, and appearance and understand the benefits the new tank would provide.
With the new tank constructed and in-service, the NPWA and their customers have increased the water quality, performance, safety, and efficiency of the system.