Understanding The Importance Of Service Flow Rate

Service Flow Rate is rarely talked about in the water softener industry simply because it's not well understood by most dealers, and because it doesn't fit into the conventional water softener sizing logic very well (a system which relies on calculations centred on water usage only).

But it's really quite an easy concept to master, and it's critically important to understand if you're interested in purchasing a softener that fits your home and will do a great job softening your water.

The concept of Service Flow Rate (we abbreviate it to SFR) recognizes the fact that the water softening process is not an instantaneous one. The water that you're trying to soften needs to be in contact with the resin long enough for the softening process to be completed. And the only thing that affects how long the water is in the softener, is the rate at which water is being demanded by your home.

What Flow Rate Can A Softener Handle?

The general rule of thumb is that for every 1.0 cubic foot of softener resin that a system is built with it will perfectly soften a flow rate of about 5 gallons per minute. If the water isn't overly hard (less than 10 grains per gallon) then the softener can likely manage a little more flow than this. Conversely, if the water is very hard (over 30 grains per gallon) the softener will likely allow a small amount of hardness to break through at 5 gallons per minute per cubic foot of resin.

How Much Water Does A House Flow?

Knowing what you now know, this is obviously quite an important question. The easiest way to understand the max flow that a home can demand is to look at the water main and measure the diameter of this pipe. We've dedicated an article on this topic here. Knowing the diameter of the pipe clearly defines the upper limit of flow that the home can draw. With that being said, most homes rarely use the maximum flow that the home is capable of.

If you want to know the max flow your home will demand and you'd like some help with this, you should check out our Water Softener Prep Kit. It comes with everything you need to test your home and your water so that you can find the softener that's perfect for your home. It includes a water-main-measuring caliper to make this measurement super easy and highly accurate.