Stable Environment

HHH Baner

Water Purity - Know Your Options

By Shari Frederick

HHH: Unlimited, clean, palatable, water is imperative for a healthy horse.
Water lubricates joints, membranes and organs, transports nutrients and wastes, maintains electrical balance in cells, and keeps your horse cool. Clean water is a source of vital fluids, essential minerals, and hydrogen and oxygen atoms. Water sources may include city, municipal, private well, or cistern water to fill troughs, buckets, and/or automatic waterers, as well as runoff to fill streams, creeks, rivers, ponds, and lakes. Horses may require between 4-20 gallons of water a day! As a general rule a 1,100 lb. horse with no work may need 4-6.6 gallons, light workers 6.6-9.2, hard workers 9.2-13.1, and lactating mares 10.5-13.1gallons.

Horse Water
Water that looks clean may contain unseen hazards such as nitrates, heavy metals, and other pollutants. Regular water-testing is advised.

HHH: Water that looks “clear” is not necessarily free from pollution or disease, and water that isn't clear is not necessarily harmful.
Unseen contaminants, such as nitrates and heavy metals, may be present in the water source. Fermenting or decomposing plant matter, common with tanks and ponds, may appear as green or yellow water and have a foul smell. Iridescence may be from petroleum contamination. Clay may cause muddiness, but generally poses no problem. Many algae varieties are harmless whereas some forms of blue-green algae that grow on pond water; especially those located near a fertilized field or slurry pit which contain lots of organic material, can be toxic. (Algae growth is more prevalent in summer.)
Horses detect tainted water easily through their keen sense of smell.

HHH: Unclean water is risky.
Unclean water can harm even a healthy horse, but immunocompromised horses, seniors and young foals, previously ill horses, and those under a lot of stress, are among the candidates at greatest risk from contaminated water sources. Some contaminants in water, such as heavy metals, accumulate in your horses’ tissues over many years, resulting in chronic health problems. Deal with water problems sooner rather than later.

HHH: Water and food introduce most environmental toxins to our horses.
Many tanks fill with rain runoff. Farming areas using chemical pesticides, herbicides, and fertilizers in their fields will contaminate water via ground seepage and flowing downstream. These contaminants, plus manure, sewage and industrial wastes, all contribute nitrates to runoff and may leave neither taste nor odor, yet they contain fecal coliform and other contaminants! Tanks and ponds from free-flowing sources are preferable to stagnant waters, which may house disease-causing organisms such as salmonella and are frequented by rodents, birds and other animals which may have infectious conditions.

Worms found wriggling in the bottom of the cats' water bucket, cleaned out and refilled the evening prior. Water attracts all kinds of visitors - check troughs often.

HHH: Water sources should be tested regularly.
Follow specific water-testing guidelines for each water source. Conduct a comprehensive test for overall water purity at each water source. Obtain laboratory approved containers and read instructions prior to taking your water sample. Never take samples on windy or rainy days, from rubber hoses, kitchen/bathroom sink bowls, or dirty areas. Let water run out the tap long enough to clear the lines (typically about 3 minutes), flame the mouth of the tap, run a little more water through the tap, then take the sample. Keep the sample on ice (don’t freeze) until it arrives at the lab, which must be within 30 hours! Follow all guidelines to assure valid results. Most health department lab results take 48 hours.

HHH: Private wells and non-city-limit water sources should also be tested regularly.
Deep wells are typically cleaner unless surface water and contaminants can get into them. They do require regular check-ups and maintenance. Wells can also harbor certain bacteria because of their oxygen- and light-deficient environment. Your county public health department can conduct a complete water test for about $250. Minimum recommended yearly water tests should include coliform, E. coli, and nitrates. When suspicious water variances appear, re-check, or conduct a more extensive test based on symptoms.

1-888-395-1033 for the wellcare® Hotline, a non-profit organization managed by the Water Systems Council of Washington DC. They have a wealth of “well” information and will also mail a packet upon request after answering questions by phone.

1-800-673-8010 for National Sanitary Foundation International (NSF), an independent, non-profit, non-government-run organization that certifies products, writes standards for food, water, air, and consumer goods (60 years of experience), and provides programs and services, continuing education, and training.

For water information also check the front of your local yellow pages under the government section for 1) Department of Environmental Protection 2) Department of Natural Resources 3) Department of Environmental Quality.

HHH: NSDWRs are non-enforceable guidelines regarding contaminants in drinking water.
National Primary Drinking Water Regulations (NPDWRs) are the legally-enforceable standard, set by the US Environmental Protection Agency (EPA), formally advised by the National Drinking Water Advisory Council (NDWAC), with input from representatives from water utilities, environmental organizations, and public and general groups. NPDWRs are regulated by each state (or tribe) for public water systems. NPDWRs list “maximum contaminant” levels. The NDWAC is a 15-diversified-member committee created by the Safe Drinking Water Act.

National Secondary Drinking Water Regulations (NSDWRs) are aesthetic standards that allow even fewer contaminants (recommended but not enforced by the EPA).
See for the office of Ground Water and Drinking Water. EPA safe drinking water hotline is 1-800-426-4791.

HHH: If air pollution is not present, rainwater is a great option for horses.
Without the addition of man-made pollution, rainwater is essentially pure. Acid rain comes from airborne natural elements and man-made pollution. Storage tanks can simply hold roof runoff collected from downspouts. (Human consumption of rainwater requires education and involves an investment in the pressure tank, pumps, filters and a UV light sterilizer.) The major source of rainwater contamination in a non-air-polluted area is the roof from which the rain drains, the gutters and downspouts that channel it, and the final storage container. Rainwater can be an alternative to toxic fluoride-treated water sources whose fluoride salts can inhibit gut and muscle enzymes, and affect calcium and magnesium levels in the body.

HHH: Nitrates are said to be the most common pollutant to which our horses are exposed.
Nitrates occur naturally in soil and water and are the primary source of vital nitrogen for plants. Excess nitrates occur when more nitrogen is added to the soil than plants can use, leaving the excess to leach into groundwater and wells. On-site sewage systems (such as septic tanks and lagoons) also can be a source of nitrate pollution.
Nitrate is converted into very toxic nitrite in the cecum of horses, who have (like infants) nitrate-converting bacteria. Once in the body, nitrite diminishes the vital oxygen-carrying capacity of the blood.

HHH: Equine nitrate poisoning indicators include bluish/brownish discoloration around eyes and mouth.
Discoloration of non-pigmented areas and mucous membranes, a staggering sluggish gait, frequent urination, labored breathing, rapid heartbeat, chocolate brown blood and convulsion may be followed by collapse, coma, and even death in severe cases. Call your vet. If treated in time, the horse may fully recover.

HHH: There are no legal or regulatory nitrate standards for horses (and livestock).
Mature horses' recommended limit is 100mg/L of nitrate.

HHH: Overly acidic water may cause vital minerals to be removed from the body.
Check the pH of your horses’ water using common litmus paper, available at your local hobby shop or pharmacy. Pure water has a neutral 7.0 pH; below 7 is the acid range, above 7 is the alkaline range. Wells should range from 6.5-8.5. Water over 8.5 pH may cause a white film/crusty scaling residue on buckets, horses, and tack or blankets. These are only inconveniences, whereas of more concern are over-acid pH health risks which include cancer, EPM and other environmental issues. Minerals can become chemically bonded in the digestive tract because of overly-acid pH. Low salt levels contribute to acid build-up in some potentially cancerous cells. Lead and zinc are more soluble in acid water -at 5.0 water corrodes lead pipes - releasing toxic lead into the water and into your horse. In this way, water softeners running through lead pipes can also cause lead poisoning!

HHH: Stallions are prone to urinary calculi if limited to only hard water.
Some deep rock springs and deep wells have hard water which contains large concentrations of magnesium and calcium with proportionately lower sodium. For prevention of kidney or urethra stones, try a tablespoon twice a week of apple cider vinegar in hard water. When washing horses and equipment in hard water, prevent a dull film by adding water softener or vinegar.

HHH: A chlorine shock process is often suggested to chemically disinfect contaminated well water.
A quick fix for a positive coliform water test is a chlorine shock. A 100-400% chlorine concentrate can be held for 12-24 hours in a well and the entire water system (faucets, toilets, water softeners, iron and sand filters, etc.), running the water through each source until chlorine is detected (by smell), to eliminate water-borne diseases. (This shock process will negatively affect carbon or charcoal filters and reverse osmosis units by using up their capacity to de-chlorinate - remove or reroute prior, or replace after, shocking.) If the bacteria problem is not eliminated, additional permanent water treatment systems will be necessary.

HHH: Study the purification options based on your test results and specific needs to maintain a clean water supply.
Choose your water purification devices wisely. Information about the various treatment options is provided by the Water Quality Association (; Find a Professional; then search for your treatment of choice by company name, county and state, or zip code).

Water treatment system choices include the following. Some systems and devices may need to be used in conjunction with others, some should not - some fit within systems or on the end of a faucet or hose, or both. Check with product manufacturers for more details. Keep in mind that some systems (i.e. reverse osmosis, distillation, and filtration) may remove valuable minerals needed for your horse's survival and well being.

Chlorination - This is the most commonly used disinfection treatment, but it requires filtering and other methods to remove the chlorine. Chlorine, fluorine, and bromine are toxic and cause damage to the thyroid. Hazardous gas results from chlorine mixing with some substances - read label cautions. Chlorine systems vary, using low levels of free residual chlorine dosages in a solid tablet, liquid or gas (the latter used more municipally), through a pump, injector, or jet aspirator, time-released and held for a minimum of 20-30 minutes. The higher the chlorine concentration and water temperature, the lower the pH, and the longer the contact, the more complete the disinfection.

Superchlorination is an alternative using more chlorine and less contact time. Activated carbon faucet filters then de-chlorinate the water and eliminate the strong taste.
Dilutions needed for effectiveness vary according to your water quality. A pond, or any surface runoff, may naturally contain ammonia nitrogen in the water which, when combined with chlorine, makes the chlorine 25% less effective (and produces hazardous gases and substances). Chlorine also loses effectiveness at pH 8 and above, and may increase cancer risks when combined with organic matter. Chlorine reacts with decaying plant materials and other organic matter to form troublesome chemicals that need additional treatments and filtering. The chlorination system itself requires maintenance, including freeing up sticking valves and clogged orifices, removing accumulated deposits, and cleaning strainers twice a year. Use chlorine as recommended by the system manufacturer, and always store chlorine in the dark to maintain potency.

Kinetic degradation fluxion (KDF) - This is a relatively new type of filter made of pure copper and zinc alloy. KDF removes chlorine, hydrogen sulfide (the rotten egg smell), lead and other inorganic contaminants through a chemical reaction using principles of electrochemical oxidation reduction. This filter inhibits microorganisms, and may be 10 times more effective than carbon filters in removing chorine, but not as effective at removing gases and volatile organic chemicals.

Pasteurization - This system raises and holds water temperature above 140 ۫ F, which kills all pathogenic organisms without chemicals, is relatively expensive to operate, and can only treat a small amount of water at a time. This system uses a lot of electricity, especially in the heat-up/ cool-down phases, and is more cost-effective to operate at least 12 hours at a time. The heating element needs to be replaced in 3-5 years. Occasionally the tank (usually steel) may need disinfecting and the coiled retention tube (pasteurizer) may need flushing.

Ozone - This system is costly to buy, operate, and maintain, but is effective against viruses and bacteria, eliminates most taste/odor, is not affected by pH, ammonia or temperature, and results can be measured at the point of treatment. Fewer disinfection byproducts are created than with chlorine, although ozone does create the byproduct bromate, which is known to increase the risk of cancer. Cryptosporidium and Giardia (parasites) are not destroyed.

Iodization - This system is similar to chlorination but costs 20 times more because iodine is more costly to obtain than chlorine. Iodine doesn’t react with ammonia, but causes some allergies, and has a slight smell/ taste. It’s preferred by NASA, the US Forest Service, and armed forces. Iodine will disinfect up to pH 10. Contact with the iodine crystals must be 15 minutes or more. Because there are no moving parts, it's easy to maintain this system. Iodine, chlorine, or bromine (tablets or drops at 10 per quart) can be used when boiling isn't possible, such as for emergency water disinfection. (Boiling, while it can effectively disinfect, doesn’t remove lead or other minerals; the loss of water through steam when boiling actually increases their concentration and potential risks.)
Raw water, with high levels of dissolved solids, contains pathogenic organisms which iodine resin effectively kills.

Ultraviolet light - Water exposed to ultraviolet light is instantly disinfected without chemicals. In time, the UV light's intensity diminishes and more electricity is needed for it to work. Lamps with 'auto safety' last 1-3 years if cleaned 2-3 times a year; non-safety models need to be replaced 2-3 times a year. Filters are needed to remove particles from blocking the light; shut-off safety devices are needed. UV requires little maintenance, has no taste/ odor. Testing verifies effectiveness. Not effective against Cryptosporidium and Giardia.

Silver - Silver in excess is considered poisonous, yet in doses well below EPA limits is a safe and strong disinfectant, helps prevent bacterial buildup, and is insecticidal (avoid using this water near beneficial insect hangouts). For this system, a carbon or diatomaceous earth filter is required along with frequent backwashing and replacement. This is a small, simple unit leaving no taste or odor, but requiring a longer contact time than chlorine. Silver and carbon filters do not mix - there are some unknowns, especially concerns about silver interacting with chemical toxins and other substances.

Water softening - Water softeners 'soften' hard water and lower nitrate levels. Deionization is one means to soften water; in this process, a resin is needed - regeneration of the resin is required using sodium hydroxide and hydrochloric acid. Both are hazardous substances that are even more corrosive to pipes than the hard water the process is trying to eliminate. Regular water softeners add sodium chloride (salt) in exchange for removing calcium and magnesium. A briny waste is discharged, which can cause septic system failure within ten years. A salinity test, total dissolved salts (TDS), is probably the most reliable indicator of water quality. TDS for horses should not exceed 7,000 ppm, although at this level there will be a strong taste. Pregnant and lactating horses require a lower salinity.

Reverse osmosis - This expensive filtration and softening system wastes a lot of water and is slower than ion-exchange water softening. Minerals and chemicals are removed as well as 95% of contaminants, including bacteria. Microscopic holes (tears) in the filtering membrane can allow microbes to pass through; therefore only microbiologically safe water should be run through (prior to reverse osmosis, chlorine can disinfect water but must be followed by carbon filter to remove chlorine). The main filtering membrane should be replaced every 1-3 years.

Anion exchange - This method uses resins charged with high concentrations of negatively charged chloride anions (hydroxide) which are used to remove high levels of nitrates, sulfates, phosphates, arsenic, bicarbonates, mercury, and fluoride. Chloride, however, will be in the finished water.

Distiller - This may produce 50 gallons per day of steam distilled water. See Minerals are removed along with chemicals. Volatile organic compounds must be separated out before distillation to avoid getting chloroform in the reservoir. There are no parts to replace. Scale buildup must be removed periodically.

Portable hose tips and mechanical filters - These are used at the tap or hose end to remove silt, iron particles, algae, sand, and some microorganisms, although effectiveness depends on the filter size and the size of the particles in the water.

Oxidizing greensand filter - This removes iron, hydrogen sulfide gas, and manganese. Periodic backwashing and regeneration with chemical potassium permanganate are necessary for best results.

Carbon filtration - Activated carbon filters come as pressed carbon block or packed granular activated charcoal, both of which remove large particles. An in-line cartridge is used to remove stirred-up sediment. All require regular replacement because they can harbor bacteria. These filters remove chlorine and its taste/ odor, and absorb contaminants, although not all chemical pollution. Effectiveness depends on size, carbon amount and length of time the water comes in contact with the filter. Speed and pressure may sacrifice purity. Larger units remove pesticides, radon, solvents, trihalomethanes, gasoline and other volatile organic chemicals. They moderately remove lead, mercury, and other heavy metals; they do not significantly remove fluoride, magnesium, nitrate, calcium, and most metal ions. Backwashing is necessary. Test the water to know when a filter needs replacing. Not compatible with silver-treated water.

This type of filtration is effective in straining out protozoa and worm eggs and other large organisms, yet is not effective with viruses; possibly effective against bacteria, but water pressure needs to be reduced.

Microfiltration - This system uses filters with less than 0.2 microns to physically screen out microbes. Cryptosporidium and Giardia and other microbial contaminants can be filtered out at the 0.1 range. An iron filter (filters out iron) uses potassium permanganate.
Activated aluminum oxide cartridges - These cartridges reduce arsenic and fluoride concentrations. Bacteria may accumulate; therefore replace cartridges periodically. Testing verifies effectiveness.

Sediment trap/settling basin - This removes black sulfur particles by holding water 24 hours or more, then allowing gravity to pull particles out of suspension. Hydrated aluminum sulfate or cheaper, more effective, polymer compounds can be added to encourage particles to combine.

HHH: Don’t be naïve - ignorance is no longer an excuse. Test all water sources at least once a year!
There is no such thing as an infinite source of pure clean water. Groundwater is in short supply and rivers cannot meet state allotments. Avoid waste, overconsumption, and the use of chemicals on the soil. Help stop pollution of water supplies. We live in a chemicalized world. Know what your horses are consuming through their water supply - conduct testing on all water sources at least once a year and supply the safest water to both you and your horses!Hoof Print


About the author:


Shari Frederick BS, NMD, LE began her love of horses in 1975, showing quarter horses at the Fort Worth, TX stockyards. As a nutritional educator in over 15 countries worldwide over the past 25 years, she is a staunch supporter of "Truth in Labeling" for ALL manufacturers. Shari has a regular column in "Equine Times" and is a Safety-Certified Riding Instructor from the AAHS. She and her horse have proudly served as the Bugler for annual cattle drives at the legendary (Texas) YO Ranch for over 15 y