Jan 06, 2024

Guest view: Water softeners, a hard problem

Water softeners reduce the “hardness” of the water in your household, which can have several benefits for consumers. Less soap and detergents are needed for laundry and cleaning. There is less staining, spotting and scaling on appliances. Clothes last longer and there are energy savings in water heating due to less scaling.

But the use of water softeners can also have harmful effects on the environment. Additional salts into our wastewater make it difficult for treatment plants to meet regulatory requirements. Harmful salts also add to the salinity of our groundwater basin.

How does a water softener work?A typical water softener utilizes an ion exchange, which involves the exchange of the hardness minerals, chiefly calcium and magnesium, for sodium (salt) or potassium (potassium chloride).

The exchange takes place by passing water that contains hardness minerals over ion exchange resins in a tank.

The calcium and magnesium contact the resin as they travel through the resin tank, displacing sodium or potassium ions. The displaced sodium or potassium ions pass downward through the resin “bed” and out the softener drain and into the sewer system. This is how the softener delivers “soft” water, but it also delivers salty brine to our wastewater treatment plant. This is where the problem begins.

The Problem

Every wastewater treatment facility in California must meet strict limits issued by state and federal agencies on the amount of total dissolved solids (TDS) and mineral concentrations to protect groundwater. If a wastewater treatment facility is found to be in violation of its discharge limits by these agencies, significant fines may result.

The discharge of salt brines into the wastewater collection system from the use of water softeners has a negative impact on recycled water and wastewater effluent. Higher salinity increases the treatment costs and reduces the potential for beneficial reuse of wastewater for irrigation of high-value crops and landscaping, and industrial purposes.

It can also impair a wastewater treatment agency’s ability to comply with discharge standards for TDS.

Sodium has little redeeming value in the environment—outside of saltwater or brackish water ecosystems. It has been cited as the biggest contaminant affecting water supplies in California, the nation and the world.

To compound the problem, the local groundwater basin has naturally occurring salt and minerals.

Plus, our groundwater basin is essentially a “closed loop” basin. This means water rarely leaves our basin unless there is a large storm event that swells the San Benito River to where it can push water through to the Pajaro River. This was the case during this year’s storms.

Because of this configuration, in dry and average rainfall years water is allowed to percolate back down into our aquifers and adds mineral content to the groundwater supply.


The City of Hollister, Sunnyslope County Water District and the San Benito County Water District collaborated on the Hollister Urban Area Water Project that allowed more surface water to be treated locally. The West Hills Water Treatment Plant and the Lessalt Water Treatment Plant process surface water brought into our county from the Central Valley Project. This water has much less mineral content than local groundwater.

Several benefits result from treating more surface water and blending it with groundwater. The City of Hollister and the Sunnyslope County Water District have been delivering higher-quality drinking water to all their customers than in years past. It is still not “soft” but has much less minerals than pure groundwater.

This has increased the quality of wastewater that is treated at the local reclamation plants. Higher quality wastewater assists in meeting discharge requirements, helps to protect the groundwater basin and helps to produce high-quality recycled water that can be used again.

These are the reasons why new installations of water softeners that use salt and/or potassium have been banned in the service areas of the two urban water providers (Sunnyslope County Water District and City of Hollister).

Solving the salinity problem in our water supply will require a community-wide effort.

If you currently own a water softener, the Water Resources Association of San Benito County (WRASBC) has a free service where they will assist you in adjusting your water softener for maximum efficiency. They also offer a rebate program for those customers who would like to demolish their water softeners or transition to a salt-free water conditioner. The rebate for demolishing your old water softener is $300.

Another option, if you truly have a need for soft water, is to transition to an off-site regeneration service where a service provider picks up the salty brine leftover from the regeneration of your softener and processes it outside our county. If you choose this option, a one-year service contract is required, and the rebate is $250.

Just make sure a WRASBC technician inspects your old water softener before disposing of it so you can take advantage of the rebate.

To make an appointment call 831.637.4378.

Shawn O. Novack is Water Conservation Programs Manager for the Water Resources Association of San Benito County, and the San Benito County Water District.

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How does a water softener work?The ProblemSolution