InspectAPedia ^®

WATER SOFTENERS - operation, maintenance, adjustment, and water softener effect on drinking water and on septic systems.
SepticAPedia ^©

• Water softeners: what is a water softener, how does a water softener work?
• What is the impact of a water softener on septic systems?
• Water softener salt, potassium permanganate, and water volume impact on septic systems
• How to adjust, clean, & maintain a water softener
• How to winterize and de-winterize a water softener to prevent freeze damage
  
• How do we managing the amount of salt in drinking water?

Water Softener suggestions for minimizing the impact on septic systems, and suggestions about salt in drinking water

Water softeners remove unwanted minerals from the water supply using one of several methods discussed here. The mineral deposits on the dripping water pipe in the photo at left are evidence of both a protracted leak and hard water. But if a water softener is improperly adjusted, or if it is not working properly, excessive salt or softener backwash discharge, if sent into the septic tank and leach fields, can damage or reduce the life of the septic system.

This document explains what "hard water" is, describes how water softeners work, and tells readers how to be sure that the salt used by most water softeners does not become a problem for people drinking the water nor a problem for the septic system. Where septic systems are already in trouble, we describe how to reduce the load on the septic system by making some changes to how the water softener is used and how its discharge is handled.

Readers should also see WHAT CAN GO INTO TOILETS & DRAINS?, a guide which explains how to extend the life of the septic system by being careful about what goes into it. Citation of this article by reference to this website and brief quotation for the sole purpose of review are permitted.

Use of this information at other websites, in books or pamphlets for sale is reserved to the author. Technical review by industry experts has been performed and is ongoing - reviewers welcomed and are listed at "References." This document is a chapter of Inspecting, Testing, & Maintaining Residential Septic Systems an online book on septic systems.

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WATER SOFTENERS - Water Hardness, the Need for Water Softeners, and their Effect on Septic Systems

Water "hardness" refers to the level of unwanted minerals, principally calcium and magnesium, found in your water supply. Hard water is an aesthetic issue (poor lathering, spots on dishes) and a mechanical issue (clogged pipes, expensive repairs, poor washing machine performance) but it is not a health concern. Hard water is found only in certain neighborhoods and usually only on private water supplies from a local well or wells.

"Water hardness varies throughout the United States. If you live in an area where the water is "soft," then you may never have even heard of water hardness.

But, if you live in Florida, New Mexico, Arizona, Utah, Wyoming, Nebraska, South Dakota, Iowa, Wisconsin, or Indiana, where the water is relatively hard, you may notice that it is difficult to get a lather up when washing your hands or clothes."--"Common water measurements", USGS - see "More Reading". Municipal water is required by federal law to be treated and tested for sanitation, hardness, corrosivity, and other features.

You may sense that water is "hard" in a building if you find that you can't get a lather in the shower when shampooing, if you find lots of spots on dishes after washing them, poor performance of a washing machine, mineral deposits on plumbing fixtures such as a mineral ring around the tip of a faucet or in a toilet bowl, and mineral clogging of the tankless coil if you make your hot water using such a device.

Minerals dissolved in "hard" water precipitate out in building plumbing pipes and fixtures where they form a hard calcium/magnesium deposit which can severely clog piping and fixtures.

The photo at left shows a cross-section of scale build-up in a building water supply pipe.

How do we Measure Water Hardness - Table of Water Hardness Grains

Hard water is generally taken to mean water containing minerals over 121 mg/L, micrograms per liter of water, or over 7 grains of hardness per gallon. The following table is based on information from the Canadian Mortgage and Housing Corporation, CMHC.

Water Softeners Impact on Septic Systems - US EPA Information

Onsite Wastewater Treatment Systems Special Issues Fact Sheet 3 - EPA 625/R-00/008

Description of the Effect of Water Softenes on Septic Tanks & Drainfields

Home water softeners, which periodically generate a backwash that is high in sodium, magnesium, and calcium concentrations, can affect wastewater treatment processes and the composition and structure of the infiltration field biomat and the underlying soil. However, attempts to predict whether impacts will occur and to estimate their severity are difficult and often inconclusive.

Water softeners remove "hardness" (dissolved calcium and magnesium) through ion exchange processes. Incoming hard water passes through a tank of containing high-capacity ion exchange resin beads supersaturated with sodium. The calcium and magnesium ions in the water attach to the resin beads, replacing the sodium, which is released into the water. The softened water is then distributed for use throughout the house.

Over time, the ion exchange resin beads become saturated with calcium and magnesium ions. When this occurs, the tank must be recharged by flushing with a salt brine solution. Sodium ions reclaim their position on the resin beads, and the calcium and magnesium ions are released into the backwash water. The backwash water then exits the tank and is discharged to the wastewater treatment system. The number of times the tank is recharged and the amount of wastewater generated depends on a number of factors, including the hardness of the water, the amount of water used, the size of the water softener, and the capacity of the resins to remove calcium and magnesium.

The wastewater generated during the recharge phase of the water softening process mixes with other household wastewaters, enters the septic tank, and eventually moves to the soil adsorption field. Studies conducted by soil scientists at the University of Wisconsin and the National Sanitation Foundation conclude that the wastewater effluent generated from properly operating and maintained water softeners will not harm onsite systems that are designed, operated, and maintained appropriately. Specifically, the studies conclude the following:

• High concentrations of calcium and manganese in the softener backwash water have no deleterious effect on the biological functions occurring in the septic tank and may, in some cases, be helpful.
• The additional volume of wastewater generated (typically about 50 gallons per recharge cycle) is added slowly to the wastewater stream and does not cause any hydraulic overload problems.
• . Soil structure in the soil absorption field is positively affected by the calcium and mangnesium ions in water softener effluent (Corey et al., 1977).

Regarding the last conclusion, some people have the misconception that the salt brine that enters the ion exchange tank also exits the tank as wastewater. In fact, the influent with its high concentration of sodium ions is very different than the effluent, which has a high concentration of calcium and magnesium ions. Consequently, the potential for chemical clogging of clayey soil by sodium ions is reduced. The calcium and magnesium input may even help improve soil percolation.

Risk management issues Regarding the Effect of Water Softenes on Septic Tanks & Drainfields

The human health impacts of ingesting softened water are increasingly discussed in addition to the traditional benefits of reduced use of surfactants and plumbing repair requirements. The choice of the homeowner to soften or not to soften will factor into all arguments. Also, the preceding descriptions are predicated on whole-house-supply softening. Today point-of-use devices designed for use with specific features in the house make the traditional advantages and disadvantages less clear.

...

Technical Reviewers & References

Search InspectAPedia

• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WATER SOFTENERS
  DETECT HARD WATER
  MEASURE WATER HARDNESS
  HOW SOFTENERS WORK
  HEALTH RISKS
  SALT OR WATER INTO SEPTIC
  REDUCE IMPACT OF SOFTENER
  SOFTENER ADJUSTMENT & CLEANING
  OTHER SOFTENER METHODS
  Winterize Water Softener & Treatment Equip
  Restoring Water Softener & Treatment Equip

WHAT CAN GO INTO TOILETS & DRAINS? - what is ok or not OK to flush into septic tanks and drainfields?

WATER SOFTENERS
  DETECT HARD WATER - how we can detect and measure the hardness of water
  MEASURE WATER HARDNESS - what constitutes hard water & how we measure water hardness
  HOW SOFTENERS WORK - how does a water softener work
  HEALTH RISKS - what are the health risks from salt in water softeners? What can be done to totally avoid salt?
  SALT OR WATER INTO SEPTIC - how to adjust the proper settings that control water softener operation, and how to perform water softener maintenance to assure that the water softener is effective in treating hard water, it will avoid wasting water, and if a private septic system is installed it will significantly reduce the chances that a septic system will be damaged by flooding or by excessive salt due to water softener malfunction.
  REDUCE IMPACT OF SOFTENER - suggestions for reducing the impact of water softeners on septic systems and reducing or avoiding salt in water for health reasons.
  SOFTENER ADJUSTMENT & CLEANING - details of how to adjust and maintain a residential or light commercial water softener for proper operation.
  OTHER SOFTENER METHODS - other ways to soften water
  Winterize Water Softener & Treatment Equip - how to prevent freeze damage to water treatment equipment
  Restoring Water Softener & Treatment Equip - how to return water treatment equipment to operation

WATER TESTING GUIDE - how, when, and why to test water for contaminants or other impurities

• North Dakota Standards for Water Softeners, North Dakota General Authority Law, Chapter 62-04-08, Water Softener Units http://www.legis.nd.gov/information/acdata/pdf/62-04-08.pdf. "The objective of this chapter is to provide a standard of quality, capacity, and performance for water softener units. Water softener performance is to be based upon referee tests procedures described in section 62-04-08-09."
• Culligan Mark 10 Water Softener 1994-1998 Installation and Operating Instructions (covering models manufactured after 1995) (1-96) 01881948.pdf available from www.culligan.com
• Water Softeners, CMHC, Canadian Mortgage and Housing Corporation, cmhc-schl.gc.ca/en/co/maho/wawa/wawa_005.cfm - October 2008. Canada Mortgage and Housing Corporation acknowledges the contribution of Health Canada to the development of this document. For further questions regarding water treatment and water quality, contact Health Canada at watereau@hc-sc.gc.ca or call 613-957-2991 or 1-866-225-0709.
• "Commercial Water Softener Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia) for commercial, industrial and residential application www.ibcwater.com.au (07) 3219 2233
• "Non electric water softener, Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
• "Water Softener Twin Tank Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
• Our Water Hardness Table used at originated with but was edited and added to from http://www.bestfish.com/tips/110598.html and also from http://www.water-research.net/hardness.htm
• Andress, S., and C. Jordan. 1998. Onsite Sewage Systems. Virginia Polytechnic Institute and State University, Civil Engineering Department, Blacksburg, VA.
• Corey, R.B., E.S. Tyler, and M.U. Olotu. 1997. Effects of Water Softner Use on the Permeability of Septic Tank Seepage Fields. In Proceedings of Second National Home Sewage Treatment Symposium. Pub. no. 5-77. American Society of Agricultural Engineers, St. Joseph, MI.
• Mancl, K.M. 1998. Septic Tank Maintenance. Ohio State University Extension publication AEX-740-98. Ohio State University, Food, Agricultural and Biological Engineering. Columbus, OH.
• University of Wisconsin. 1978. Management of Small Waste Flows. EPA-600/2-78-173. U.S. Environmental Protection Agency, Cincinnati, OH.
• U.S. Environmental Protection Agency (USEPA). 1992. Manual: Wastewater Treatment/Disposal for Small Communities. EPA 625/R-92/005. U.S. Environmental Protection Agency, Cincinnati, OH.
  

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
• ...

More Information on Building Diagnostic Inspections and Repairs

• "Common water measurements" from the USGS - http://ga.water.usgs.gov/edu/characteristics.html
  "Hard Water Hardness Calcium Magnesium - Water Corrosion Mineral Scale", Wilkes University, http://www.water-research.net/hardness.htm
  "Septic Tank/Water Softener, potential effects of water softener use on septic tank soil absorption on-site wastewater systems; the effect of home water softener waste regeneration brines on individual aerobic wastewater treatment plants," Water Quality Research Council, Water Quality Association, 477 E. Butterfield Road, Lombard IL 60148
  "Source Water Protection Practices Bulletin, Managing Septic Systems to Prevent Contamination of Drinking Water", US EPA, http://www.epa.gov/safewater/protect/pdfs/septic.pdf
  "Sodium and Chloride and Water Softeners", Michigan DEQ at http://www.deq.state.mi.us/documents/deq-wmd-gwp-SodiumChlorideWaterSofteners.pdf
  
  The following references were found at http://www.caitechnologies.com/water-softeners/effects-of-water-softener-discharge-on-septic-systems.htm
  "A Quantitative Analysis of the Impact of Salt on the Microorganisms in an Aerobic Wastewater Treatment System", S. Husain & C.D. Litchfield, referenced NOWRA & WQA Septic-Softener Symposium, (12/2005 NOWRA newsletter)
  "To Soften Or Not To Soften", Water Quality Research Council, WaterReview Technical Brief, (1988 Vol. 3, No. 2, revised 09/1992)
  "The Effect of Home Water Softener Waste Regeneration Brines on Individual Aerobic Treatment Plants", The NSF International, (07/1998)
  "Effects of Water Softener Use on the Permeability of Septic Tank Seepage Fields", R.B. Corey, E.J. Tyler, and M.G. Olotu, Home Sewage Treatment, Proceedings of the Second National Home Sewage Treatment Symposium, ASAE Publication 5-77. American Society of Agricultural Engineers, St. Joseph, MI. (1977, pp. 226-235)
  "Onsite Wastewater Treatment Systems Special Issues Fact Sheet 3", EPA 625/R-00-008, Environmental Protection Agency Fact Sheet (2000)
  "The Effects of Electrolyte Concentration, Cation Adsorption Ratio, and the Septic Tank Effluent Composition on Hydraulic Properties of Natural Swelling Soil Systems", B.A. Alhajjar, University of Wisconsin-Madison (1981)
  "Home Water Treatment System Discharges to On-Site Wastewater Systems", J.F. Harrison, C.F Michaud, Water Conditioning & Purification Publication, (12/2005, pp. 34-39)
• The Septic System Information Website home page for this topic
• Septic Systems Inspection, Testing, & Maintenance- online textbook. Detailed how to inspect, maintain, repair information
• The Home Buyer's Guide to Septic Systems
• Cesspools Home Buyer's or Owner's Advice
• Cheating on Water Tests - (Chlorine in Wells and Septics) Testing Water for Real Estate Transactions - Water Test Cheating Warnings for Home Buyers and Home Inspectors
• Clogged Drain Diagnosis - is the problem the septic system or the Building drain system?
• Contamination in Buildings how to test buildings for bacterial contamination from Sewage and Septic backup, remediation, & references
• Drywells Home Buyer's or Owner's Advice
• Leach Field Inspection Procedure Septic Leach Fields - how to inspect and diagnose septic drainfield failures - what causes septic field failure?
• Septic Treatments, Additives & Chemicals: Septic System Maintenance - Are they even needed? Are they even legal?
• Septic Biomat Formation in the Septic System Drainfield Absorption System - what leads to drain field clogging and expensive drainfield repairs
• Septic Buyer's Guide Home Buyer's Guide to Septic Systems Inspection & Testing - What to Do, Step by Step.
• Septic Maintenance: Ten Steps to Keeping a Septic System Working, suggestions from the U.S. EPA, edits and additions by DJF
• Septic Tank Pumping Guide: When, Why, How to pump the septic tank
• Sewage & Septic Backups and what to do about sewage spillage in buildings
• Tank Location - How to Find the Septic Tank, how deep will the cover be, how to document its location
• Tank Pumping Frequency Guide for Septic Tanks: When, How, What to Watch For when pumping or cleaning septic tanks
• Water Usage: Capacity: Determining Needed Septic Capacity - Typical residential water usage for people, appliances, and activities.
• What is a Septic System An Engineer's View & Septic System FAQ's

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting