Clack Valve Models Explained: WS1, WS1.25, WS1.5, WS2 and Twin Valves
Sep 30, 2026The short version: Clack’s “Water Specialist” valves are named mostly by pipe size. The WS1 is the 1-inch valve that fits most homes. The WS1.25 is the 1.25-inch version for higher-flow homes and light commercial work. The WS1.5 and WS2 are larger valves for commercial jobs. Twin versions, like the WS1TT, run two tanks so one is always in service. Letters after the number usually describe the controller or the configuration.
The model number is mostly the pipe size
| Model | Size | Typical use |
|---|---|---|
| WS1 | 1″ | Most single-family homes; softeners and filters on 6″–21″ tanks; 27 gpm service flow |
| WS1.25 | 1.25″ | Larger homes, high-flow fixtures, light commercial. Shares a service manual and parts family with the WS1 |
| WS1.5 / WS2 | 1.5″ / 2″ | Commercial and large-flow systems on bigger tanks |
| Twin alternating (e.g., WS1TT) | 1″ | Two tanks; one serves while the other regenerates, for soft water around the clock. Clack lists the WS1TT at 28 gpm service flow |
From Clack Corporation product literature.
What the letters after the number mean
Clack adds letters to tell you about the controller and setup, such as twin-tank versions or different electronics. The core of the valve, the piston and seal stack, is shared across a family, which is why one service manual covers the WS1 and WS1.25. If you’re ordering a part, the full model on the label matters; if you’re choosing a softener, the size and the setup matter far more than the suffix.
Softener valve or filter valve?
The same WS1 body is set up differently depending on the job. As a softener it draws brine from a salt tank to recharge the resin. As a filter (carbon, iron, sediment) it only backwashes and rinses, with no brine. Clack valves can run three ways: meter immediate (regenerate as soon as the resin is used up), meter delayed (wait until a set time, usually overnight), or time clock delayed (on a schedule). For most homes we use meter delayed so regeneration happens at night when nobody is showering.
Which size does a home need?
For most homes in Bradenton, Lakewood Ranch, Parrish and Sarasota, the WS1 is the right valve. It moves enough water for several fixtures at once. We step up to a WS1.25 for very large homes, homes with body-spray showers or big irrigation tie-ins on treated water, or small businesses. Bigger isn’t automatically better: an oversized system costs more and can regenerate less efficiently.
Metered vs. time clock: why it matters here
Older softeners regenerate on a timer, every few days whether you used water or not. A metered Clack valve counts the gallons and regenerates only when the resin is close to used up. On Manatee County water, which runs up to about 16 grains per gallon, that difference adds up: a household that travels or has guests on and off can waste a lot of salt and water on a timer. Meter delayed, regenerating overnight after the resin reaches its set capacity, is what we use on most homes.
Upflow vs. downflow brining is the other setting you may hear about. Both work; the right one depends on the media and the tank. It’s set during installation and isn’t something a homeowner needs to change.
How to find the model on your softener
Look on the valve cover or the label on the valve body. The model is usually printed there along with a serial number. If the label is faded from the sun, take a clear photo of the valve and the display and text it to us at 941-266-8991. We can usually tell from the photo.
Common questions
What is the difference between a Clack WS1 and WS1.25?
Pipe size and flow. The WS1 is a 1-inch valve that fits most homes; the WS1.25 is a 1.25-inch version for higher-flow homes and light commercial use. They share a service manual and many parts.
Which Clack valve do I need for my house?
Most single-family homes use the WS1. Very large homes or high-flow fixtures may need a WS1.25. Size depends on your flow, hardness and household, so we measure before recommending.
What is a Clack twin alternating valve?
A twin valve like the WS1TT runs two resin tanks. One tank is always in service while the other regenerates, so you have soft water 24 hours a day. It’s common in commercial use and very heavy-use homes.
Can the same Clack valve run a softener or a filter?
Yes. The WS1 body is set up as a softener (with brine) or as a backwashing filter for carbon, iron or sediment media.
Where is the model number on a Clack valve?
On the valve label or cover. If it’s faded, send us a photo of the valve and display and we’ll identify it.
Are Clack WS1.5 and WS2 valves for homes?
Rarely. They are larger valves meant for commercial and high-flow systems on bigger tanks.
Not sure which valve or size fits your home? We test your water free and size the system to your household. Call or text 941-266-8991.
Related: Clack WS1 review · Clack WS1 error codes · Softener sizing in Florida · Fleck vs. Clack · Commercial water systems
Sources: Clack Corporation product pages and WS1/WS1.25 and WS1.5/WS2 service manuals (clackcorp.com).
