Water Softener Salt Effects on Drinking Water, Plumbing Systems, Heating Equipment & Septic Systems

Salt or Water Loading of the Septic System
- Will the Water Softener Salt or Water Volume Damage the Septic System?
- Water hardness or softness - mineral level - effects on heating equipment, plumbing systems, boilers, water heaters, piping & tankless coils
Questions & Answers about the effects of water softener or water conditioner salt on drinking water & on septic system life
References

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Water Softener Salt Effects on Drinking Water & on Septic Systems - water softener salt problems: this article explains the effects (and potential damage or harm) of water softeners on septic systems. Also see REDUCE IMPACT of SOFTENER on SEPTIC and see OTHER SOFTENER METHODS for examples of water treatment & water softening methods that do not use salt or ion-exchange.

Salt or Water Loading of the Septic System: Will the Water Softener Salt or Water Volume Damage the Septic System?

At HEALTH RISKS & WATER SOFTENERS we introduced possible health concerns for salt added to drinking water by a water softener. Also see REDUCE IMPACT of SOFTENER on SEPTIC. Also see SOFTENER ADJUSTMENT & CONTROLS where we provide details about water softener setting and salt dose adjustments.

Some septic system experts assert that salt discharged into the leach field is an important factor in shortening the life of the biomat which forms below the leach field (to treat effluent as part of the sanitizing process for septic effluent).

Certainly high levels of salt can kill septic tank or drainfield bacteria.

But a normally-operating water softener is unlikely to harm the septic system.

We start by agreeing that a malfunctioning water softener may damage a septic system in two ways:

Water volume in Septic Fields from Water Softeners: The normal water softener backwash cycle is less than 100 gallons and is not a major source of daily water usage at a property (see "Determining Needed Septic Capacity" at "More Reading" below).

If the timer or valve gets stuck in the "backwash-on" cycle (which I have seen happen), the system will run continuously and will flood the septic leach field. This is discussed in "Clogged Drain Diagnosis" referenced at "More Reading" below.
Salt dose of Sodium and Chloride in Groundwater from Water Softeners: Part of the water softener backwash water contains no extra salt. During an interval of backwash however, some water may be quite salty, perhaps 5,000 ppm to 10,000 ppm.

If the salt dose (which is also adjustable on many water softeners) is set incorrectly high excessive salt may be discharged into the septic system where it may damage the leach field and its biomat.We encountered this condition at a property where the owner had first set the salt dose to the maximum and then set the backwash frequency to a maximum as well, when neither was needed for the level of hardness of the water.

A Michigan DES study of community wastewater treatment systems (not private septic systems) reported that sodium and chloride in the soil at their discharge sites greatly exceeded federal drinking water limits.

This point needs more research since it's not clear that groundwater is required to meet drinking water standards - this is a shortcoming of the Michigan article.

The article continued to cite 120 m/l for sodium and 250 m/l for chloride as the maximum allowable levels in groundwater. (See "Sodium and Chloride and Water Softeners" at "More Reading".) On further research I will update this section.
Water softener salt at normal levels will not kill septic tank bacteria

Normally the water softener salt and chloride should not be a problem for the septic system: One of my clients is a biochemist who specializes in studying septic bacteria.

His opinion was that in a normally-working home water softener system the level of water softener-produced salt in the septic tank was so diluted by other water flowing into the tank that in his experience it never reached a level that was harmful to septic tank bacteria.

We are not sure if this same conclusion applies to bacteria in the drainfield biomat. Gayman and others have conducted research on salts in drainfield soils and their role in drainfield life.

Normally water softener water volume should not be a problem for the septic system. See REDUCE IMPACT of SOFTENER on SEPTIC and then be sure to read SOFTENER ADJUSTMENT & CONTROLS to be sure that your water softener is operating properly.

Water Softener Maintenance Tip: Should You Use Potassium Chloride (KCL) ?

Some water softener manufacturers such as for the Sears Kenmore electronic water softener recommend using potassium chloride "salt" (KCL) instead of standard sodium chloride (NaCL) which is standard or ordinary salt. and remark that potassium chloride salt will give longer equipment life and will permit lower hardness settings on the water softener control. Kenmore explains that if you are not using KCL in their water softener you might need to increase the equipment's hardness settings by 25%:

If your softener does not have a KCl salt setting, you must increase your hardness setting by 25% to ensure continuous soft water.[21]

Watch out: Sears-Kenmore warns:

A softener using KCl should not be placed in areas with temperature fluctuations and high humidity (KCl will harden in these environments and may make the softener inoperable.

Check the brine tank and brinewell (black tube in salt storage tank) monthly. If hardening is present, pour small amounts of warm water onto hardened areas until they loosen. [21]

Effects of Water Hardness or Softness on Plumbing & Heating Equipment, Heating Boilers, Water Heaters, Tankless Coils

Effects Hard Water (high in mineral content) on Building Piping, Water Heaters, Heating Boilers, Tankless Coils

The effects of water that is too high in mineral content are widely understood to lead to mineral deposits in building plumbing systems and heating equipment. The percipitation of minerals out of hard water into or onto plumbing and heating components is generally more rapid and extreme at points of highest temperature in the system, but the effects of hard water on building mechanicals are also a function of the volume of water moving through the system. In sum, for hard water, the effects on building piping, heating equipment, water heaters, and tankless coils is a function of

The hardness level of the water
The volume of water that is run through the plumbing system, boiler, water heater, or tankless coil over time
The temperatures of the water as it moves through the equipment
The surface properties of the equipment. For example, using an acid flush to clean a tankless coil also leaves the coppe surface inside the coil etched and rougher than when new - possibly meaning that even with no change in the other parameters above, the time to clog-up again with minerals may be less than when the equipment was new.

Tankless coils used on heating boilers to product domestic hot water are particularly prone to clogging from minerals in hard water, as we discuss in detail at Clogged Pipes / Tankless Coil De-Scale

Hydronic heating boilers themselves are less affected by hard water because except in the case of chronic leakage, the water placed into a hydronic heating boiler system is static - we are not normally constantly introducing new water and more minerals. However water chemistry is nevertheless important in some heating system applications, and special additives may be used to protect the system. Discuss this quesiton with your heating service company.

Steam boilers, unlike hydronic heating boilers, may indeed suffer from high mineral content in hard water, as new or makeup water is regularly requried and added (manually or by an automatic fill valve) in steam heating boiler systems. And as we just cited, water chemistry is nevertheless important in some heating system applications, and special additives may be used to protect the steam heating system.

Water heaters used to produce domestic hot water indeed suffer from scale formation from hard water. See WATER HEATER SCALE - De-Liming Procedure and WATER HEATER SCALE PREVENTION for details.

Effects of Soft Water (very low in mineral content) on Water Heaters & Heating Boilers

Lochinvar® LLC, a producer of high efficiency boilers, water heaters, and pool heaters, has produced an interesting technical bulletin that warns installers and building owners about special considerations when their equipment (and most likely that of other manufacturers when the heat exchanger is made of copper) is installed in buildings served by a water softener. [20] Quoting:

The required temperature rise and the standard pump used with Copper Heat Exchangers is based on the presumption of typical water chemistry of 8 – 25 grains of hardness, and less than 350 ppm dissolved solids (TDS). Caution must be used when heating water softened water below 8 grains. Typically commercial water softeners reduce hardness to 0 grains which may result in long term problems in the system.

When using softened water the installer must be aware that increasing temperatures causes an increase in the speed of chemical reactions. The rate of increase of chemical reactions approximately doubles for every 25 – 30 degrees Fahrenheit rise in temperature up to about 160 degrees F. The rate of water flow governs the rate at which the dissolved oxygen (essential to corrosion) is replenished at metal surfaces. Typically the corrosion is characterized by pitting resulting from metallic hydroxide and tuberculation reaction. Metal hydroxide dissolves the metal, and tuberculation reduces the hydraulic capacity of the tubing. Since this aggressive reaction typically happens at the metal to flow interface early heat exchanger failure can be expected.

Water heaters can be used in softened water but it is imperative that careful attention be paid to the heat exchanger. Proper operation will normally require setting the water heater with a lower flow rate and higher temperature rise.

Decreasing the flow rate will reduce the erosion process, however the heat exchanger should be monitored to ensure the scale/liming process is not exacerbated. The unit should be placed on a comprehensive inspection schedule until optimum flow rates can be established. Problematic water areas may require heat exchanger inspection every two weeks. The total scale accumulation should never exceed the thickness of a piece of paper. Should scale accumulation exceed this thickness the flow rate will need to be increased. The tubes should not have a bright shiny copper look. This would indicate that the erosion process has begun and the flow rate will need to be decreased. Once the proper flow rates have been established the inspection intervals can be increased to every 30 days, once a quarter, to a bi-annual inspection.

This procedure should insure proper operation of the unit as long the water quality stays consistent.
- Lochinvar, LLC World Headquarters, 300 Maddox Simpson Pkwy., Lebanon, TN 37090, Tel - Customer Service: 615-889-8900, contact Lochinvar Technical Service at 1-800-722-2101, Website: http://www.lochinvar.com/ [20]

The company's technical bulletin includes a table that relates heater BTU Input Rates (between 90,000 & 500,000 BTUH), and Delta T at 0-7 grains of hardness compared with Delta T at 8-25 frains of hardness. We note that the higher the BTUH firing rate of the heating equipment, the higher is the required Delta T (temperature rise). For example,

a 90,000 BTUH input water heater [using a copper heat exchanger] handling water at 0-7 grains of hardness has its Delta "T" set to 8 degrees, while the same device handling water at 8-25 grains of hardness uses a Delta "T" of 5 degrees.
a 135,000 BTUH input water heater [using a copper heat exchanger] handling water at 0-7 grains of hardness has its Delta "T" set to 12 degrees, while the same device handling water at 8-25 grains of hardness uses a Delta "T" of 7 degrees.
a 500,000 BTUH input water heater [using a copper heat exchanger] handling water at 0-7 grains of hardness has its Delta "T" set to 40 degrees, while the same device handling water at 8-25 grains of hardness uses a Delta "T" of 28 degrees.

So you can see there is a significant change in temperature requirements for high-BTUH equipment.

Extensive quotation & technical review requested of Lochinar 12/15/12

Frequently-Asked Questions (FAQs) about water treatment equipment and their effect on septic systems

[Also please see the Q&A section at SOFTENER CLEANING & SANITIZING].

Question: slimy scum water softener problems along with septic system failure - due to water softener?

Since I installed my water softner, I've noticed a few changes.

The first was a slimy scum that had formed in my main line water filter. Upon further investigation, this scum was also forming inside the toilet tanks.

The second thing that I noticed was a break-down of my septic system. I have a double septic tank that was pumped out a year and a half ago. I went five years without having to pump it since there is only my wife and myself at home. There is now a puddle of pungent water that keeps appearing over top of the septic tank.

These could be coincidental, but I think not since it was never a problem until the softner unit was installed. - Neil 4/11/12

Reply:

Neil,

I suggest following the procedures at SOFTENER CLEANING & SANITIZING, followed by a test of your water supply (ahead of the water softener) for contaminants. It also sounds as if you have two problems: unsanitary water in the home and a failing septic system.

A relationship between the water softener & septic could be that the softener's regen cycle is flooding the septic system tank & fields, but a puddle over the septic tank could be caused by other septic problems too. So also see SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR.

For more depth of understanding of the possible issues, also see

Frequently Asked Questions (FAQs)

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

[1] 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."
[2] 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
[3] 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.
[4] "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
[5] "Non electric water softener, Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
[6] "Water Softener Twin Tank Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
[7] 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
[8] 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."
[9] 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
[10] 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.
[11] "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
[12] "Non electric water softener, Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
[13] "Water Softener Twin Tank Installation and Operating Instructions", IBC Filtration & Water Treatment Products (Australia), op.cit.
[14] 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
[15] Andress, S., and C. Jordan. 1998. Onsite Sewage Systems. Virginia Polytechnic Institute and State University, Civil Engineering Department, Blacksburg, VA.
[16] Corey, R.B., E.S. Tyler, and M.U. Olotu. 1997. Effects of Water Softer 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.
[17] 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.
[18] University of Wisconsin. 1978. Management of Small Waste Flows. EPA-600/2-78-173. U.S. Environmental Protection Agency, Cincinnati, OH.
[19] 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.
[20] "Softened Water Impact on Water Heaters, Bulletin Number: 2004-02I", Lochinvar High Efficiency Water Heaters, Boilers & Pool Heaters, Lochinvar, LLC World Headquarters, 300 Maddox Simpson Pkwy., Lebanon, TN 37090, Tel - Customer Service: 615-889-8900, contact Lochinvar Technical Service at 1-800-722-2101 web search 12/15/2012, original source: http://www.lochinvar.com/
Lochinvar United Kingdom 7 Lombard Way The MXL Centre Banbury, Oxon OX 164TJ Phone: (01295)-269-981 Fax: (01295)-271-640 Web: www.lochinvar.ltd.uk
[21] Kenmore Water Softener Use & Care Guide, Model 635.383000 (with a high flow valve), retrieved 2/14/2013, original source: http://c.sears.com/assets/own/896150e.pdf [ copy on file as Kenmore_Softener_No.625.383_Manual.pdf ]
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Soil Percolation Tests soil perc testing guide and instructions
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF. Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers. Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill.
Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers:
* Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF. Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
Submissions welcome. send us a suggested document link or request an exchange of website links

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

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

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Onsite Wastewater Disposal, R. J. Perkins; Quoting from Amazon: This practical book, co-published with the National Environmental Health Association, describes the step-by-step procedures needed to avoid common pitfalls in septic system technology. Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers, consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index.
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