United States ThermoAmp Inc. has manufactured its Heat Siphon swimming-pool and spa heat pumps in Latrobe, Pennsylvania, since 1983. Founded by Bill Bernardi after he led pool-heat-pump development at EUS, the privately owned company continues to ship its equipment worldwide and has built its identity around in-house engineering, titanium heat exchangers, and patented corrosion-isolation technology. Its portfolio also includes wireless and built-in WiFi controls for monitoring and managing pool heating.
Hayward Industries, IncFor a century, Hayward Industries has manufactured equipment and connected technology that keep residential and commercial pools running, from pumps and filters to automation and water-quality systems. Founded in 1925, the company operates globally from its Charlotte headquarters and maintains four U.S. manufacturing facilities, where more than 3.8 million products were made in 2025. Hayward says 87% of its 2025 sales value came from U.S.-manufactured products, while its Omni systems bring remote control and monitoring to the pool and outdoor-living experience.MEDFORD, NY
Cardinal Systems IncFounded in 1976 in a 5,000-square-foot garage, Cardinal Systems Inc. is a family-owned American manufacturer of customizable swimming pool and spa products, with custom fabrication capabilities for other industries. Now operated by the Bradley family’s third generation, the company works from a 350,000-square-foot Schuylkill Haven facility and has grown to more than 340 employees across its divisions. Its manufacturing portfolio includes Cardinal and Fox Pool brands, along with Quaker Plastics and Cardinal Fabrication & Manufacturing.SCHUYLKILL HAVEN, PA
Endless PoolsFounded in 1988, Endless Pools is a Philadelphia-area aquatic fitness company known for pioneering the swim-in-place current. Its compact pool systems serve home users, commercial facilities, and competitive swim programs in more than 100 countries, and the company is the official swim spa supplier of USA Swimming and the U.S. Swim Team.339920ASTON, PA
PDC SpasPDC Spas, founded in 1957 as Plastic Development Company, is a privately held Pennsylvania manufacturer of hot tubs and swim spas. Its Williamsport craftsmen design and produce the spas at the same West Fourth Street location where the company rebuilt after a 1983 facility fire. The company also makes fiberglass products and introduced its patented TruSwim propulsion swim spa series in 2018.WILLIAMSPORT, PA