This article describes the various options for correcting unsanitary or unsatisfactory drinking water.

Various water treatment methods for contaminated water are reviewed and the pros and cons of each are discussed.

This series of articles explains many common water contamination tests for bacteria and other contaminants in water samples. We describe what to do about contaminated water, listing common corrective measures when water test results are unsatisfactory.

Water Treatment for Contamination, Hardness, Odors, Sediment, Etc: choices of systems, recommendations

A comprehensive list of water treatment articles is provided here. We discuss water treatment methods and we also include water testing and water correction measures warnings for home owners and especially for home buyers when certain conditions are encountered, with advice about what to do when these circumstances are encountered.

Article Contents:

• WATER TREATMENT EQUIPMENT CHOICES
  • WHEN to INSTALL a WATER TREATMENT SYSTEM
  • WATER TREATMENT METHODS TABLE
  • WATER TREATMENT RELIABILTY & SAFETY

See WATER TESTS for CONTAMINANTS for advice on using a private well for drinking water.

When is it reasonable, desirable, or actually necessary to install water treatment equipment:

• Time does not permit thorough diagnosis
  
  and determination of the source of water contaminants (you have to move in and drink the water, or the bank won't issue the mortgage for a property purchase)
• Water potability appears to be unreliable
  
  a bacteria problem may have been temporarily masked or "corrected" by "shocking" the well in the past but follow-up testing suggests that it returns, perhaps seasonally as water tables change.
  
  See "WELL CHLORINATION & SHOCKING - Procedure for Shocking a Well to (temporarily or maybe longer) "Correct" Bacterial Contamination".
• There is a persistent source of water contamination 
  
  a potability or health issue is in the supplying aquifer - not a condition that can be fixed by repairing a well casing, piping, equipment, or by well shocking.
• There is a persistent source of an aesthetic water problem
  
  hard water, sulphur odors (rotten eggs), iron, or other such contaminants.
• When people in a residence are at unusual health vulnerability
  
  immune impaired, elderly, sick.

 

Principal Methods Used to Treat or Purify Contaminated Drinking Water

While we distinguish between having to treat water because it is not potable - that is, the water is not safe to drink, and wanting to treat drinking water because of an aesthetic concern like odor, taste, smell, or staining, it is often the case that the equipment used for one purpose can also address the second set of concerns.

Watch out: few if any water treatment or water purification systems can reliably remove all possible water contaminants that may be present in a water supply or may be contributed by contamination of the building's water supply system & equipment. While a "bacteria test" is a good starting point in checking on the safety of drinking water, a check with local water testing labs (and neighbours) can give critical advice about other contaminants that might be present in your water supply and for which tests should be performed.

See WATER TREATMENT RELIABILTY & SAFETY for details.

• Activated carbon or charcoal water filters:
  
  effective for taste & odor removal including chlorine. Some activated charcoal filters complying with U.S. Standard-53-Water Filter Certification can remove heavy metals such as copper, lead, mercury, chlorine or other disinfectant byproducts, parasites like Giardia or Cryptosporidium, pesticides, radon, VOCs, and certain other chemicals such as dichlorobenzene and trichloroethylene (TCE).
  
  Watch out: if not properly selected, and if not changed or renewed on schedule any filter including charcoal filters can convert from being effective at reducing or removing water contaminants to harboring them and even dispensing them into the water supply.
  
  See WATER FILTERS, HOME USE for a discussion of home water filters used for sediment, odors, etc.
• Aeration treatments 
  
  for water supply systems involve the injection of air into the water supply. Aeration treatment can reduce some odors and is effective for low to moderate levels of iron provided that the water temperature is not too low. Therefore aeration treatment is more effective in warm climates and where water levels are at a higher pH. Aeration is often combined with a filtration system for water treatment for iron. Aeration is not an effective water purification method.
• Boil the water
  
   to make it suitable for drinking.
  
  See BOILING WATER for DRINKING
• Bleach the water
  
   to disinfect it: Use chlorine (bleach, sodium hypochlorite) to purify the water. (see warnings just above).
  
  See BLEACH DISINFECTANT for DRINKING WATER
• Calcite media filters
  
  Calcite media water treatment filters adjust the pH of the water to make it less corrosive (when the startign water pH is at a pH of 5.5 or less) and also to precipitate ionic iron or ionic magnesium from the water supply so that it can be captured by the water filtration system.
  
  Calcite media filters are used principally when water staining that shows up in the water itself or on plumbing fixtures or on laundered fabrics is itself traced to rusty or corroded water mains or in-building water supply pipes (steel or iron piping).
  
  See CORROSIVITY or ACIDITY of WATER
• Ceramic water filters
  
  ceramic water filters are capable of removing a broad range of water contamniants and are frequently adapted to portable, camping, or emergency drinking water systems.
  
  See FILTERS for DRINKING WATER PURIFICATION
• Chemical Coating systems
  
  a chemical feeder / coating system using sodium silicates along with polyphosphates is used to protect copper water supply piping that is being attacked by a water supply with a high oxygen content.
  
  A polyphosphate feed system may be installed on a building where the water supply is green due to dissolved copper leached from copper piping and / or where green stains are showing up on plumbing fixtures or on fabrics laundered in water from such a water system.
  
  See GREEN STAINS from WATER SUPPLY
• Chemical Feed / Neutralization Soda Ash
  
  water treatment systems dispensing a soda ash chemical feed are used to correct high water pH (acidic) conditions by injecting a base (soda ash) into the water supply followeed by filtration. Soda-ash injection to correct acidic water requires a pump and metering device along with an intermediate tank to give the water enough contact time with the soda ash.
  
  Water high in natural acids or high in carbon dioxide (CO2) are acidic and are likely to need a treatment of this type.
  
  See CORROSIVITY or ACIDITY of WATER
• Chlorination
  
  where electrical power and water pressure are present and the equipment is already installed, a chlorinator or water chlorine injection treatment system (a chemical feed system), usually combined with a charcoal filter for water treatment may be functional as a water disinfection method (to treat bacterial contaminants).
  
  Chlorination also can remove high concentrations of ionic iron, ionic manganese and tannins as well as organic contaminants that left alone contribute to iron/manganese loving bacterial problems in the water supply system.
  
  See CHLORINATORS & CHARCOAL FILTERS for details.
• Colloidal silver
  
  has been used in and has limited application for water purification. Warnings about the limitations of colloidal silver for water disinfection to make drinking water potable or safe
  
  See COLLOIDAL SILVER for WATER DISINFECTION
• Distillation of drinking water
  
  Use a water distiller such as a home or portable distillation unit like the portable Sears® Kenmore home water distiller shown at DRINKING WATER EMERGENCY PURIFICATION [live link just below].
  
  A distiller removes contaminants such as heavy metals and can treat parasites or bacterial pathogens (if you boil the water long enough).
  
  Water is boiled and the purified steam is then recondensed. You'll need electrical power or a source of heat to distill water).
  
  This device processes about one gallon of water per cycle. We have been using this Sears Kenmore water distiller, model 5000 for more than fifteen years without a hitch.
  
  A disposable charcoal post-distillation filter is available for use in the drip spout of the unit - a potential source of contamination if it is not changed occasionally.
  
  See DISTILLATION for DRINKING WATER DISINFECTION
  and
  See SOLAR WATER DISINFECTION
• Emergency drinking water filters
  
   and camping-use or portable water filters & purifiiers
  See
  • DRINKING WATER FILTERS
  • DRINKING WATER EMERGENCY SOURCES
  • DRINKING WATER EMERGENCY PURIFICATION
• Filters for drinking water
  
  water filters are provided in a wide range of designs to remove different contaminants such as particulates, sediment, odors, iron. For potability select & use a water filter designed for water purification, particularly ceramic filters and silver-ceramic filters.
  
  See WATER FILTERS, HOME USE for a discussion of home water filters used for sediment, odors, etc.
• Iodine tablet for drinking water purification
  
  or a liquid tincture of iodine to purify the water for emergency use. See the chemical & giardia contamination warnings above.
  
  See IODINE for WATER DISINFECTION
• Iron Filters
  
  address principally aesthetic contaminants such as iron and manganese that can impart unpleasant odors, tastes, or cause staining of fabrics and plumbing fixtures. Iron/manganese reduction water filters are used when the iron + manganese level in the water supply is relatively low (less than 10 mg/L) and when the water pH is high enough (above pH 6.8) to make this approach effective.
  
  The filter media absorbs and oxidizes ionic iron and manganese. Higher levels of iron and water contaminated with iron/manganese bacteria require other treatment methods.
  
  See WATER STAINING CONTAMINANTS
  and
  See WATER FILTERS - SEDIMENT & IRON and treatment systems address sediment, iron, manganese, odors, taste
• Halogenated resins
  
   have been used for water disinfection
• Home Made & Expedient Water Sterilization Methods
  
  Matthew Stein describes a variety of home-made, expedient, and partly effective water filters and water treatment methods in When Technology Fails. With plastic and a few sticks you can build a solar water sterilizer (solar water disinfection or SODIS systems).
  
  See book recommendations found atReferences or Citations for this article.
  
  Stein also explains that slow sand filters have been used for partially cleaning and treating water for a very long time. A crude home made charcoal filter will remove some odors, bad tastes, organic toxic chemicals, and radioactive fallout.
  
  Mr. Stein also describes sari water filters used in Bangladesh after flooding, but includes a critical warning that filtering water through cloth is by no means really safe.
  
  Our favorite of his suggestions is using a plant to form a water collector and filter system, an idea which reminds us of native Americans who knew how to obtain water from desert barrel cactus.
• Hydrogen peroxide
  
   may be used (maybe) to purify water for emergency drinking use. [The concentration and exposure time data are still needed for this application.
  
  See HYDROGEN PEROXIDE for WATER DISINFECTION

• Lead filters for drinking water
  
  there are devices that can be installed on the building water supply to reduce lead originating in the building's water supply. Ort a lead filter m ay be installed as a "point of use" treatment method at the kitchen sink.
  
  However if a building's water piping (lead or brass pipes, lead water service main, lead solder joints on copper piping) or fixtures (containing lead or brass) are the principal sources of lead in drinking water, flushing the system before collecting water for drinking or cooking may also be effective.
  
  The US EPA warns that flushing may be ineffective in high-rise buildings that have large diameter supply pipes joined with lead solder.
  
  Companies advertising lead filters are given in the article cited just below.
  
  Watch out for devices sold to reduce lead in drinking water but that do not work. The U.S. EPA recommends that you should verify the lead-reduction claims of device manufacturers by checking the NSF International or the Water Quality Association.
  
  See LEAD IN DRINKING WATER, HOW to REDUCE
  where you will also
  
  see LEAD FILTERS for WATER
• Pumps with filters for water purification
  
  Use a water purifying pump such as models sold by camping equipment suppliers to purify the water - typically these pumps use a ceramic or other filter.
  
  See FILTERS for DRINKING WATER PURIFICATION for information about pump type ceramic water filters.

• Reverse osmosis - RO systems for drinking water purification
  
  RO systems use a semi-permeable membrane to separate water contaminants by taking advantage of a ready water supply in a pressurized water system. R.O. systems are often combined with an activated carbon or charcoal filter component.
  
  Reverse osmosis can remove most water contaminants including parasitges (Cyrptosporidium & Giardia), heavy metals including cadmium, copper, lead, mercury, and other common water contaminants sometimes found in the water supply itself such as arsenic, barium, high levels of nitrates or nitrites, perchlorate, and selenium.
  
  You can use a reverse osmosis water filtration system to provide emergency drinking waer if water pressure is available or if a portable R.O. system is available.
  
  See REVERSE OSMOSIS WATER TREATMENT for details. RO treatment systems may work where there is no electrical power provided that you have water pressure, such as in some municipal water situations.
• Shock the well to fix drinking water problems
  
  using a disinfectant such as bleach can cure a temporary bacterial contamination issue at a water well such as caused by spiders or insects, by having pulled well piping to work on the system, from area flooding, or other temporary conditions.
  
  But shocking a well can also mask a persistent water contamination source so follow-up testing is usually needed.
  
  See WELL CHLORINATION SHOCKING PROCEDURE
• Solar water disinfection of drinking water
  
  is a special case of using solar energy to distill water. Photocatalytic enhanced solar disinfection using NF-TiO2 was responsible for complete inactivation of E. coli in those reactors exposed to both solar and visible light radiation.
  
  The presence of NF-TiO2 enhanced the disinfection rate efficiency of E.coli when compared to those experiments where no photocatalyst was used.
  
  Practical application of dye solutions as dosimetric indicator appears as very useful for determining the solar radiation dose necessary for waterborne pathogen deactivation.
  
  SeeReferences or Citations for this article for more about photocatalytic enhnced solar disinfection.
  
  See SOLAR WATER DISINFECTION
• UV Lights for drinking water purification
  
  ultra violet light used for water sterilization. UV systems can kill bacteria and some parasites provided that sufficient exposure time and light intensity are provided.
  
  According to the NRDC, Class-A UV systems are rated as adequate against bacteria, viruse, and parasites such as Cryptosporidium and Giardia. Class-B UV water treatment systems are rated as effective against non-disease-causing bacteria (by rendering them "inactive").
  
  See UV ULTRAVIOLET LIGHT WATER TREATMENT
  
  Watch out: Because UV light water disinfection will not remove chemical contaminants and because research indicates that at least some UV treatment systems do not address some persistent cystic contaminants such as Giardia,
  
  See WATER TREATMENT RELIABILTY & SAFETY for details.
• Vinegar disinfection of drinking water?
  
  vinegar is sometimes used as a vegetable wash and may be effective against some microorganisms in water - we have not yet found authoritative data on this application.
  
  See VINEGAR for PRODUCE or WATER DISINFECTION
• Mixed oxidants for water disinfection 
  
  electrochemically generated from brine have been used for water disinfection
• Ozone for water purification: ozone or ozonization to remove contaminants from drinking water or from septic effluent discharge and some research suggests that the highly reactive oxygen molecules produced by ozone treatment may help oxidize and remove certain other contamiants in the water supply.
  
  See OZONE for WATER DISINFECTION
• Sequestration by Chemical Feed for Water Purification
  
  very high concentrations of iron in the water supply may be treated by the addition of food-grade polyphosphate to the water.
  
  The polyphosphate compunds, in a chemical reaction, "sequester" that is isolate and separate iron (Fe) molecules which keep the iron in solution in the water supply.
  
  This proces prevents iron from separating out of the water, presumably until after the high-iron-content water has been discharged as wastewater.
• Water softeners / water conditioners also referred to as cation exchange softeners
  
  are installed as permanent treatment systems for correcting "hard" water - clogs pipes, poor washing & bathing, mineral deposits, reduced hot water output from water heaters and tankless coils. A water softener swaps sodium (salt) or potassium (a salt alternative) into the water to cause calcium and magnesium as well as limited amounts of ionic iron and ionic manganese to precipitate out of the water supply.
  
  See WATER SOFTENERS & CONDITIONERS
  and also
  
  see WHITE STAINS from WATER SUPPLY
  
  Anion-exchange water softener resin for removing tannins
  
  Where there are low tannin contributions to the water supply (yellow staining) a water softener employing a special anion-exchange water softener resin is capable of removing low tannin concentrations in the water.
  
  See YELLOW STAINS from WATER SUPPLY
  
  Iron & manganese removal
  
  Water softeners and conditioners can often also remove modest amounts of iron or manganese or sulphur, but if significant levels of other contaminants are present as well as hard water, a combination of water conditioner and other water treatment steps will be appropriate.
  
  See RED STAINS from WATER SUPPLY

 

Water Treatment Safety, Reliability & Chemical Safety Warnings

At WATER TREATMENT METHODS TABLE we point out that few if any water treatment or water purification systems can reliably remove all possible water contaminants that may be present in a water supply or may be contributed by contamination of the building's water supply system & equipment.

While a "bacteria test" is a good starting point in checking on the safety of drinking water, a check with local water testing labs (and neighbours) can give critical advice about other contaminants that might be present in your water supply and for which tests should be performed.

Watch out: disinfecting water by bleach, chlorine, or similar methods will not remove other chemical contaminants nor will it reliably remove Giardia in Drinking Water - a review of the health hazards & typical equipment costs for portable and whole house water treatment to remove Giardia cysts from drinking water.

Other treatment steps such as charcoal filtration may be needed for some chemicals, and other treatment methods including ceramic filters can remove Giardia.

See GIARDIA in DRINKING WATER

Drinking water should be tested periodically, at least annually, especially if there is a known contamination issue - to make sure that the well has remained sanitary, or to make sure that the treatment equipment is working properly. Perhaps also to get lucky and find that treatment is no longer needed.

See BACTERIA LEVELS in WATER, INTERPRETATION

A minimum test is to collect a sample of treated water for this purpose. If you also test water collected ahead of the treatment system you can confirm what treatment is needed.

Watch out: Water treatment chemicals can be highly toxic or caustic and should be kept out of reach of children.

And if these watching outs aren't enough,

Watch out: following area flooding or damage from an earthquake, hurricane or other catastrophe, even if community or private wells are back in operating and providing water, do not assume that the water is sanitary and ok to drink until responsible authorities have said so. Even then, local water pipes in a building may be unsanitary and additional cleaning or disinfection may be needed.

If you are looking for camping, portable or emergency use water purification methods,

see DRINKING WATER - EMERGENCY PURIFICATION for a discussion of various methods used to purify water for hiking, campling, and emergency use as well.

In the article above we discuss water treatment, not water testing.

...

Continue reading at WATER TREATMENT EQUIPMENT DISINFECTION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• WATER STAINING CONTAMINANTS - water contaminants that result in stains on fabrics, fixtures, etc. and that may also help diagnose some water odors.
• WATER QUALITY & QUANTITY San Miguel de Allende
• WATER TEST CHOICES & WATER TEST FEES - choices of water tests and our advice about choosing among them.

Suggested citation for this web page

WATER TREATMENT EQUIPMENT CHOICES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER TREATMENT SYSTEMS

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Citations & References

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