Water Softener Service Life

The are many factors that determine the service life of a water softener.  Some water softeners need to have their resin replaced in as few as two to three years, and other units can last as much as 25 years or more.  It is typical to expect a useable service life of 10 to 15 years from a water softener, but this depends on many variables as discussed below:

Control Valve: The softener’s control valve and associated mechanical components should be of good quality.  Most better quality water softener controls (made by companies like Fleck, Autotrol, Clack, Culligan, Kinetico, etc.) have at least a 5-year warranty.  Lower quality “entry level” softeners found at many of the big box stores can last only a few years (sometimes you can identify these by their shortened 1 to 2 year warranty). It’s always important to select a good quality softener control valve when choosing a softener.

Brine tank and components: The brine tank and brine tank internal components should also be of good quality.  Typically a brine tank should be round rather then rectangular, and should include a salt platform (grid). The round tank and grid help to prevent “salt bridging”. Salt Bridging is when salt pellets solidify together after repeated regenerations, and create a "bridge" over the volume of water that is placed back into the tank by the valve/control.  This can lead to insufficient brining.  If a rectangular brine tank must be used (for instance in the case of a cabinet style softener or due to floor space limitations), then always be sure that it contains a brine tank grid.

Be sure that the brine tank also contains a good quality safety float check.  If the valve that controls the brine tank refill were to fail, it’s important that the system contains a secondary (back-up) float check valve that will prevent water from overflowing out of the brine tank.  Most better quality softeners also have a tertiary gravity overflow fitting, so that in the event that both primary and secondary valves fail, water can be directed through this fitting to a sump pump or drain location if available.

Resin Tank: Be sure that the system you purchase has a commercial quality resin tank. These tanks are available from a number of manufacturers (Structural/Park, GE, and others), and can typically carry a 10 year residential warranty.

Water quality:

a) Chlorine concentration – Although most high quality cation exchange resins used in water softeners are resistant to chlorine or chloramine attack, they are not impervious.  If your water softener is exposed to higher levels of chlorine or chloramines, then it is possible to see a shortened water softener resin bed life.  This can sometimes be a factor when you are connected to municipal water supplies.  Normal chlorine/chloramine concentration found in city water does not effect water softener resin significantly.  However, during times when there is a disruption to the normal water distribution system (hurricane, flood, pipeline break, etc.), the level of chlorine may need to be increased to assure proper disinfection.  Also, some municipalities need to inject elevated levels of chlorine because the water source contains a higher amount of bacteria, or the integrity of the distribution system is in question.  Higher levels of chlorine can cause premature resin bed failure, and it may be necessary to replace the water softener bed with new resin periodically.  This said, water softener resin will normally last throughout the life of the softener, and is not normally replaced.

b) Iron and manganese concentration – Municipal water supplies typically have very low levels of iron and/or manganese present.  However, on-site wells can contain these materials. When present as particulate ferric (also called “red water” iron), it can accumulate in a water softener’s resin bed.  If these contaminants remain within the bed, and build up over time, then resin bed failure can occur, and it is important to set a frequent regeneration & backwashing to wash this particulate to drain. The frequency of regeneration required varies depending on iron & manganese concentration, but can be as much as every day to 7 days in frequency.

It is also typical to have 5 to 10 micron pre-filtration, to remove any particulate iron and manganese from your water before it can reach the water softener. You can also consider using a commercially available blend of phosphoric acid (available under the brand names of Res-Up and Pro-Res) that is automatically added via. a drip feeder installed on the inside of your brine tank. Phosphoric acid aids in cleaning the bed of accumulated iron and manganese during the automatic regeneration process. This material is only used during the regeneration process, and does not enter your household water supply.

c) Dirt and sand – Like the iron and manganese particulate discussed above, organic sediment (dirt) and sand can be contained in your water, and a pre-filter is normally used upstream of the softener to protect the bed.  Larger sand can be removed using a sand specific filter (like a Spin-Down or SandMaster centrifugal filter), and smaller sediment is removed using an automatic backwashing filter system or inline cartridge filter.

d) Iron & sulfur bacteria - Iron and sulfur bacteria live on the outside of an iron or sulfur particle, and are "slimy".  This material can stick to water softener resin and ultimately lead to fouling of the bed. While this bacteria is not a health hazard, if present you need to first remove it from your water if planning to install any backwashing water treatment equipment (like a filter or water softener).  Chlorine injection is the preferred method to resolve this problem, but be sure to install a carbon filter to remove any injected chlorine, protecting a water softener installed downstream.

There are many other factors that can determine water softener performance and service life, but the ones discussed here are the common ones that need to be considered when purchasing a softener.