Water Conditioning, Treatment, Filtration, and Purification Systems and Supplies

Duff Co. is an industry leader in water conditioning, treatment, filtration and purification. We manufacture residential, commercial and industrial systems, as well as supply all the parts and components. But what really sets us apart is the Duff Difference. We have the best, most experienced and most knowledgeable support staff in the country. We have unsurpassed technical abilities and understanding. Our system design services specialize in solutions for all your applications. And technical support is always available to solve your problems.

Residential Systems

Whether it’s problem water or a problem with a piece of equipment, it’s a safe bet that we’ve seen it before and know the solution. For residential and commercial water treatment dealers, our tech support has been there and done that; knowing what to install is only part of the battle, of course. That’s why you can rely on us for all the best equipment in the industry.

Beyond the names you know – Clack, Pentair, Fleck, Autotrol, Structural Fibers, Pentek, Harmsco, Grundfos – we also offer certain premium proprietary systems. These product lines offer exclusive access to specialized systems, marketing support and individualized product literature, with advanced, private training opportunities.

Learn about the Aquachamp dealer programs and other exclusive product lines. The Aquachamp product line was relaunched in 2018. Learn more by contacting Duff today!

Commercial Systems

As an original equipment manufacturer (OEM) of water treatment systems and equipment, we build to your specifications. We also specify equipment. Give us a call or email us with the water conditions, and we can discuss what equipment is right for your application. From softeners to dealkalizers to filters; greensand to carbon to KDF; meter- or time clock initiated regeneration–no matter what the water chemistry, size requirements, or any other considerations: We have you covered. While we build many standard commercial units, they may vary in countless ways, including control valve, mineral tank size, mineral/resin, and so on.  For detailed information on the control valves, as well as the other components in each unit, call or email us today.


Choose Duff for all you cartridge component needs. We offer the largest variety of high performing products available. That’s why our customers rely on us as their one-stop-shop for all their filtration product needs.

Duff Co. is the exclusive Master Distributor For Pentek residential and industrial filters, as well as the American Plumber brand. We stock more cartridge filters and accessories than anyone else!

Media, Resin & Chemicals

Softening, deionization, dealkalization—our water treatment specialists have expertise in virtually any ion exchange and adsorption technology. We are dedicated to providing our customers with the right media for the job. The high quality resins we use include anion, cation, mixed bed and specialty resins. Call us today and we’ll help find the medium for your ion exchange or filtration application.

Control Valves

The brain of a water treatment system is often the multi-port control valve. If it’s a Fleck, Clack or Autotrol valve, our water treatment experts have seen it, installed it, programmed it, performed troubleshooting on it, torn it down, fixed it, and repaired it. We have the best technical experts in the business, with the most experience and knowledge. Give us a call, and find out for yourself.

Ultraviolet Lights

We sell the highest quality UV disinfection systems to combat waterborne pathogenic organisms. Our UV systems kill bacteria, viruses, and other pathogens by preventing them from reproducing.

We also offer the widest selection of replacement bulbs and parts from every major manufacturer.