Water Service

The water system:

Horsham’s public water system obtains water via a subsurface supply withdrawn from 15 wells located throughout the Township. The Authority’s collective DRBC allocation for its 15 wells is 83.36 million gallons over 30 days.

Horsham’s water system is divided into two zones divided generally by Keith Valley Road and Tennis Avenue. The high zone consists of the portion of the Township west of the above mentioned boundary delineation and the low zone is to the east.

The high zone includes two storage tanks - Lower State and Cedar Hill and three wells - 3, 7, and 19. The low zone consists of three storage tanks - Maple, Herman, and Witmer and 12 wells - 1, 2, 4, 6, 9, 10, 17, 20, 21, 22, 26, and 40.

Well 6 has been in a “reserve” (inactive status) since 2009 while the remaining 14 wells have been used regularly as active sources.

The five storage tanks have a combined capacity of 4,250,000 gallons and provide the Township with pressure equalization, fire reserve, and emergency standby storage.

Approximately 141 miles of water mains of varying sizes make up the transmission and distribution system.

There are also three active interconnections with neighboring suppliers to supplement water system demand.

The Aqua PA interconnection is located at Welsh Road and Electronic Drive in the Authority’s low pressure zone. The Aqua interconnection is permitted for up to 400,000 gallons per day, but is generally operated at approximately 225,000 gallons per day. 

The original interconnection with the North Wales Water Authority (NWWA) is located at Welsh & Llanfair Roads in the Authority’s high pressure zone. A second interconnection with NWWA located on County Line Road, north of Route 611 was placed into service in 2018 as part of the long term plan associated with the PFAS contamination (described below) and supplies water to the low zone. The two NWWA interconnections are permitted for a combined 800,000 gpd, however HWSA was granted a temporary increase to 1.2 MGD in order to accommodate the short term plan associated with the PFAS contamination (also described below). The temporary permit increase expires in September 2019, at which time the maximum permitted flow returns to 800,000 gallons per day.

Flow rates for all three interconnections are adjusted based on system demand and the operating status of the Authority’s wells. A third interconnection with NWWA is located on Lower State Road at Chestnut Creek Park. This interconnection is generally used only in emergency situations.

Generally, demand in each zone is met using water from the storage tanks within that zone. The wells in each zone begin to pump simultaneously to meet customer demand and refill the tanks when the water level in the tanks in the respective zone drops to a predetermined level. While the wells are pumping, water is being supplied throughout  the interconnected system both from the tanks and from the various sources of water entering the system. When the tanks refill, the wells turn off and water is supplied via the storage tanks. Water in the tanks is diminished and restored based on demand and the wells cycle accordingly between active and inactive pumping states.

Through the controlled operation of valves at two separate locations in the system, water from the high zone can be moved by gravity into the low zone. A single booster location allows the movement of water from the low zone into the high zone through a controlled pump and valve operation.

Historically, treatment at the wells was limited to gaseous chlorine disinfection (all wells), supplemental aeration to remove volatile organics (5 wells), and iron sequestration (1 well).


In 2014, and again in 2016, multiple wells were removed from service due to the presence of Poly- and Perfluoroalkyl Substances (PFAS), a class of chemicals that contaminated the drinking water supply after being used in firefighting foams at the former NASJRB and existing Horsham Air Guard Station. Based on detectable levels of PFOS & PFOA (two of the chemicals within the class of PFAS) above the USEPA Health Advisory (HA) level of 70 parts per trillion (ppt) combined, five wells are being equipped with filters to remove the PFAS levels at the expense of the US Navy. As of  the end of 2018, wells 26 and 40 are operating with permanent granular activated carbon (GAC) filters installed, while wells 17 and 21 are in service using temporary GAC filters. Well 10 is currently operating under a pilot permit to test single use anion exchange resin.

PFOS and/or PFOA have also been detected at levels below the EPA HA in the other nine wells however because the combined concentration in these wells is below the 70 ppt HA, the military is not funding treatment for these wells.

In light of concerns as to the evolving nature of the science regarding PFAS contamination in drinking water and the chronic, historic consumption in the Horsham community, a groundbreaking short term plan with a goal of achieving undetectable combined levels of PFOS and PFOA in the public drinking water supply was presented and adopted at a joint public meeting between HWSA and Horsham Township Council on June 26, 2016. After a presentation by HWSA of five options and hearing comments and concerns raised by the residents, Council and HWSA voted to adopt a plan that involves the installation of permanent treatment systems at the five Navy-funded wells, temporarily suspending use of eight of the nine remaining wells and replacing that production with a temporary increase in water purchased from NWWA.

This plan was overwhelmingly supported by the public in attendance at the meeting when the plan was presented. However, the short term plan carries additional costs which are not currently being reimbursed by the military and the military will only fund projects designed to meet the EPA health advisory or other future standards.

In September 2016 a PFC surcharge to cover the cost of implementing the short term plan went into effect. A majority of the cost of the short term plan is for purchased water, which costs approximately 2.5 times more than producing it from our own wells.  

A long term plan, designed to sustain the goal of the short term plan was adopted in September 2016 and involves the installation of six permanent treatment systems in addition to those being funded by the Navy. Permanent treatment systems on Wells 2, 4, 19, 20 and 22 are all under active construction and all five wells are expected to be returned to service in 2019, at which time, purchased water from NWWA will be systematically reduced. Groundbreaking on the sixth treatment system on the Aqua Interconnect is slated for early 2019. The long term plan also includes the construction of an additional interconnection with NWWA, and construction of approximately 2 miles of water mains to make public water service available to properties with private wells, both of which were completed in 2018. Following full implementation of the long term plan, the remaining wells without treatment – 1, 3, 7 and 9 will be placed in reserve status similar to well 6, such that HWSA will rely on ten wells with PFAS treatment, and three interconnections, one of which one will also be equipped with GAC treatment.   

A $10 million grant that was allocated through legislation passed as part of the 2016- 2017 state budget process is being utilized to install the long term plan infrastructure. This funding is designated for costs associated only with physical infrastructure. Operating costs, such as carbon change-out, are excluded from eligibility under this funding.

On May 14, 2018, HWSA entered into a contingent fee agreement with Anapol Weiss for professional services to pursue reimbursement and other damages from five foam manufacturers in connection with the PFAS contamination of HWSA’s water supply.

Water System Operations:

For the past 20 years, day to day operations of the water system have been carried out under a management contract with Aqua Pennsylvania (Aqua), formerly, Philadelphia Suburban Water Company. Due to the changes in the operation of the HWSA system resulting from the presence of PFAS, since mid-2017, HWSA has taken on more of a  lead role in the operation of the water system. For the first time in the history of the Horsham water system, as of January 1, 2019, Authority personnel have assumed full responsibility for the operation of the HWSA wells. Aqua will continue to support HWSA, particularly in the areas of laboratory support and distribution maintenance.

The average daily water demand of 2.2 MGD is met through a combination of water production and purchase from adjacent suppliers.