Stage 1 fire restrictions, enacted for unincorporated areas of western Boulder County.

Understanding Water Quality: Onsite Wastewater Treatment Systems

Understanding Water Quality

Understanding Water Quality: Onsite Wastewater Treatment Systems

Leaks & Water Waste

It’s not the little leak that wastes water — it’s the little leak that keeps on leaking that wastes water. The fact that the leak is so little, may also mean that you ignore it.

So, how can a little leak turn into a big waste? Many of our toilets have a constant leak — somewhere around 22 gallons per day. This translates into about 8,000 gallons of wasted water annually, which could be saved. Think of a leaky water line coming into your house. If it leaks 1 gallon of water every 10 minutes, that means that you are losing (and paying for) 144 gallons per day, or 52,560 gallons per year. The leak can also lead to failure of the OWTS because the system is overloaded.

Watershed Definition

A watershed is simply the land that water flows across or through on its way to a common stream, river, or lake. A watershed can be extensive (e.g., draining thousands of square miles to a major river, lake, or ocean) or very small, such as a 20-acre watershed that drains to a pond.

Checking Your Water Quality

If you are on a community water system, your municipality or water district should be able to answer your questions. Community water supply systems perform regular tests and will provide reports on request.

Private testing laboratories are also available and listed in the telephone book under laboratories. The Colorado Department of Public Health and Environment’s laboratory phone number is (303) 692-3500. The Environmental Protection Agency’s Safe Drinking Water Hot Line is 1-800-426-4791.

Well Water Health Concerns

As the well owner, you are responsible for assuring that your water is safe to drink. Basically, the water should be free from organisms that can cause illness. These organisms include bacteria, protozoa, viruses, and helminths (worms).

Diseases that are transmitted by water can cause anything from an upset stomach to more severe and long-term health problems. Examples of some serious diseases include typhoid fever, salmonellosis, giardia, infectious hepatitis, and others.

Learn More about Waterborne Disease

Chemical Contamination

Chemical contamination should also be a concern. For example, the amount of nitrate in the water should be a concern if you live in an agricultural area, near animal feed lots, or in other places where fertilizers are used. Nitrate levels exceeding 10 milligrams per liter can cause methemoglobinemia, commonly known as blue baby syndrome, in infants under one-year-old. Adverse long-term health effects associated with consuming nitrates also exist.

Testing Frequency

You should test for coliform bacteria, pH, and total dissolved solids at least once each year. These tests should be conducted in the spring or summer after a rainy period.

Coliform bacteria tests should also be conducted after replacing pipes or after installing a new pump. Tests should also be undertaken if water quality changes in color, odor, taste, etc., where or what you live next to can affect your water quality. If someone in your family becomes ill or the taste, odor, or color of your water changes, your supply may be contaminated.

You should test for nitrates, sulfate, chloride, fluoride, iron, manganese, hardness, and corrosion index every three years if your home plumbing contains lead material or brass fittings, test for the presence of lead.

Below is a list of situations that deserve attention.

Condition or Nearby ActivitiesRecommended Test
Recurrent gastrointestinal illnessColiform bacteria
Household plumbing contains lead pH, lead, copper
Indoor radon Radon
Scaly residue or soaps don’t lather Hardness
Is a water softener needed? Hardness, manganese, iron
Stains on plumbing fixtures or laundryIron, copper, manganese
Objectionable taste or rotten egg smellHydrogen sulfide, corrosion, metals
Water appears cloudy, frothy, or colored Detergents
Nearby agricultureNitrate, pesticides, coliform bacteria
Odor of gasoline or near gas station Volatile organic compounds
dry-cleaning business nearby Chloride, metals
Dump, junkyard, landfill or VOC’s TDS, pH, sulfate

A Positive Coliform Bacteria Test

The presence of coliform bacteria indicates that the water system has been contaminated from an unspecified source. Water containing coliform bacteria may also contain disease-causing organisms and is considered unsafe to drink.

In time, bacteria can develop or grow in any well. Sooner or later, bacterial growth will occur if organic material is present in the well.

The presence of coliform bacteria may be due to a structural defect that allows contamination to enter the well. A good drilled and cased well normally has a 6-inch casing that extends down at least 100 feet and 1 foot above the ground surface. The top of the casing has a cap, which is called a sanitary seal.

Some wells are just hand dug down to the water table. Hand-dug wells usually have larger openings and are challenging to protect. Any openings in the well structure that could allow entry of surface water, rodents, or insects into the well should be corrected before trying to eliminate the bacteria. Openings should be covered to provide a water-tight seal. Sometimes a cover which overlaps a rim can be made to give a shoe box-type fit. Any vent should be directed downward and screened off.

If you are unfamiliar with wells, contact a pump installer or well service business.

A contaminated well can often be disinfected. Contact your county health department for instructions on disinfecting your contaminated well. Some wells may need to be disinfected more than once to destroy the problem organisms.

Safe Disposal of Household Chemicals

Boulder County operates a central household hazardous waste collection facility that accepts most household hazardous wastes (HHW), including motor oil, antifreeze, and other automotive products; garden, hobby, and pet products; drain cleaners; pool chemicals; household batteries; paint and other home maintenance products.


Located at 5880 Butte Mill Road, Boulder (one-half mile east of 55th Street and Pearl Parkway, inside the Western Disposal Transfer Station); the HHW hotline is (303) 441-4800.


The facility is open for waste drop-off (no appointment necessary) each Wednesday from 8:00 a.m. to 3:30 p.m. and Friday and Saturday from 8 a.m. to 12 noon.

During open hours, the facility also holds a product giveaway, when reusable products are made available to the public free of charge. Please note: the facility is not open on public holidays and may close in extreme weather. Please call (720) 564-2226 to check for closures or for more information.


There is no charge, but it’s not free. Boulder and Broomfield Counties fund the Household Hazardous Waste Program, as do the cities of Boulder, Lafayette, Longmont, and Louisville and the towns of Erie, Nederland, and Superior. Each city pays for its residents’ participation, and the county pays for participation by small-town and unincorporated area residents.

The program serves all Boulder County residents, the County of Broomfield, and the Town of Erie residents. This includes the following communities: Allenspark, Boulder, Broomfield (All City of Broomfield residents), Erie (All Town of Erie residents), Jamestown, Lafayette, Longmont*, Louisville, Lyons, Nederland, Niwot, Superior (Boulder County residents only), and Ward. Proof of residency (i.e., driver’s license, voter identification, tax certificate, lease agreement) is required when you drop off waste.

The City of Longmont hosts its event in the fall. For more information, call the Public Works Division at (303) 651-8416.

For additional information, visit the County Resource Conservation Division.

Keep Colorado beautiful, healthy, and safe. Contact the Colorado Department of Public Health and Environment at (303) 692-2035 for more information on hazardous household wastes and their disposal.

Safe Disposal of Automotive Chemicals

Residential wastes can be handled in the same fashion as listed in the answer above.

Boulder County operates a central household hazardous waste collection facility that accepts most household hazardous wastes, including motor oil, antifreeze, and other automotive products; garden, hobby, and pet products; drain cleaners, pool chemicals; household batteries; paint and other home maintenance products.

For the most part, automotive wastes can be taken to participating filling stations, oil and lube businesses, and some garages. Many locally operated landfills will also take these items. Other commercial wastes would need to be hauled by a licensed hazardous waste disposal contractor to dispose of the waste properly.

Call the Colorado Department of Public Health and Environment at (303) 692-2035 for more information on how you can help keep yourself and your community healthy by safely disposing of automotive waste.

Please Note: This information is intended to provide a better understanding of the functions of onsite wastewater treatment and the need for proper design, installation, and maintenance. Always consult a licensed professional or public health official with questions regarding the engineering, installation, and servicing of onsite wastewater systems.

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