Water Softeners

Better Water Quality Begins With Each of Us


With talk of drought, rising sea levels, and the state's proposed water tunnels, many are concerned that there may be an increase in water salinity in the Sacramento-San Joaquin Delta. Controlling all sources of salinity is necessary to protect water quality.

Referred to as total dissolved solids or TDS, salinity is concentrated dissolved mineral salts in water, including calcium, magnesium, sodium, sulfate and chloride.

Salinity comes from many sources, a major one being salt water from the San Francisco Bay that flows into the freshwater of the Delta. Other sources include natural weathering processes, agricultural and storm runoff, and recycled water discharged from sanitary collection systems that may include byproducts from household and industrial cleaning agents.

Most of ISD's sewer water comes from homes and businesses in ISD's service area of Oakley and Bethel Island. This sewer water has the potential to contain a fair amount of salinity which will run through the district's system and into the Delta. It is important to minimize the salinity that enters the sewer system, as ISD's recycled water is first used to irrigate agriculture fields and the rest is released into the San Joaquin River.

How Can You Reduce Salt in the Sewer?


Household cleaners, astringents and water softeners contribute to salinity in the sewer system. One solution, in addition to using natural cleaning products, is to use disposable wipes and cleaners that can be put in the trash. Another is to use "exchange" water softeners.

There are generally two types of home water softeners available: self-regenerating and exchange systems. Both types remove calcium and magnesium, the minerals responsible for "hard water" scale that can shorten the life of plumbing and appliances. However, the exchange system does not require the homeowner to add salt or use potable water in the cleaning process.

As part of the self-regeneration process, a strong brine solution (made of common salt) is flushed through the system to remove minerals that accumulate in the water softener. The brine waste byproduct is typically discharged into the sewer system. A single residential self-regenerating water softener can discharge a pound of salt per day and between 70 to 300 gallons of water per week when it regenerates.

Exchange softeners remove the same minerals found in hard water but, rather than disposing the waste salt and water into the sewer, the brine is held in tanks for recycling by a water softening company that discharges it into a permitted facility where it will not affect water supplies.

So, eliminating a self-regenerating system is a leading way to help control salinity in the sewer water coming from your home or business. If you have a self-regenerating water softener, consider trading it for a more environmentally friendly exchange softener.

Other Resources


ISD's Board of Directors recently adopted a Salinity Pollution Prevention Plan (PDF), which outlines sources of salinity in Oakley and Bethel Island's wastewater. The plan addresses ways to reduce the levels of salinity that reach the sewer system and are ultimately released into the environment.

Following the lead of Discovery Bay and dozens of California communities, ISD is working to develop an ordinance that would restrict the new installation of certain types of water softeners at homes and businesses. The restrictions may take effect in early 2015. A workshop and public hearing will be held prior to adoption of the ordinance.