Germicidal UV-C Applications > Home/Residential UV-C Systems > Failed Water Test
What is a failed water test?
A water test analyzes contaminants and water quality indicators (WQIs) found in the water supply. A failed water test may indicate that there is too much of a particular microorganism that could be harmful in the water and that renders it unsafe to drink or use.
Whether your water comes from a private well or a public source, having your water tested is the first step in protecting yourself and your loved ones from ill-effects caused by potentially bad water. Once you know what you’re dealing with from the results of your water analysis, you can adequately treat your water and regain peace of mind.

Why do I need to take a water test?
Testing your water is the first step in protecting your health. If you receive your water from a well, it is an essential part of maintaining a safe water source. Changes in the appearance, taste, and smell of your water are easily recognizable concerns. However, according to the EPA’s Drinking Water from Household Wells , potentially severe contaminations from bacteria, heavy metals, nitrates, radon, and other chemicals that are naked to our senses can only be determined through testing.

Other potential sources come from past or present human activity — things that we do, make, and use — such as mining, farming and using chemicals. Some of these activities may result in the pollution of the water we drink.
— Environmental Protection Agency, “Drinking Water From
Household Wells”
Your water test should include analysis for total coliform bacteria, nitrates, total dissolved solids, and pH levels. Experts recommend you also speak with your county health department for additional substances you should screen for based on your well’s geography and surrounding agriculture or industry. For more information on your particular state’s guidelines, visit Private Drinking Water Well Programs in Your State .
How do I know when to take a water test?
Groundwater is always moving. As a result, there is the endless opportunity for your water source to become contaminated. More than 15 million U.S. households use private water wells , and the well’s owner is responsible for overseeing the safety and quality of the water. Experts recommend testing the well’s water annually by a certified laboratory. More frequent testing may be necessary if there is cause for concern.




If your well is shallow, aging, located near livestock, septic systems, landfills, or manufacturing plants, there is more opportunity for contamination. Pregnant women, babies, infants, elderly, or immune-compromised people are more susceptible to the ill effects of contaminated water. If these individuals reside in or visit your home frequently more regular testing is suggested. Even if your water comes from a municipal water supply, there are still plenty of reasons to have your water tested.
Most of the country’s pipes and water systems were designed and installed over 100 years ago. Large municipalities and cities nationwide have staff that monitors water quality around the clock. Many smaller communities aren’t able to keep up with monitoring their water quality and maintaining their aging infrastructure as required by the Safe Water Drinking Act (SDWA).
If your water source is public, you should receive an annual Consumer Confidence Report from your utility containing important information regarding the water’s quality. Unfortunately, according to a May 2017 report by the Natural Resource Defense Council (NRDC) titled “Threats on Tap: Widespread Violations Highlight Need for Investment in Water Infrastructure and Protections,
Our research shows that in 2015 alone, nearly 77 million people were served by more than 18,000 community water systems that violated at least one SDWA rule, and there were more than 80,000 violations of SDWA rules that year
— NRDC, “Threats On Tap”
Regardless of your water source, regular testing is an easy and valuable way to educate yourself about the quality of your water and take control by installing a water filtration and disinfection system on your water supply.

The following changes, in general, indicate it’s time for a new water test:

Symptoms such as nausea, diarrhea, cramping, vomiting, or headaches

Water is off-color, cloudy, or has an odor

Reduction in water pressure
In addition, if your water is from a private well:
If the following factors are present, you should also get your water tested.
- Flooding, storm surge, or tornado activity
- Increase in construction or agriculture activity
- Increase in mining activity or a recommission of an old mine (if your well is within a quarry’s pumping zone of influence including strip mining, open-pit mining, and mountaintop removal mining, or underground mining such as for coal)
- Known issues with neighboring septic systems or cesspools
- Repair to pipes, pumps, and/or the well casing
- Recently decommissioned well in your area
- If your well is newly drilled or bored larger

Or if your water is from a public water source:
Get your water tested regularly if your municipality frequently issues boil water alerts and is often plagued by water main breaks and other infrastructure failures.
Selling Your Home
Many municipalities and mortgage companies require mandatory water analysis that tests–at a minimum–bacteria, nitrate, and lead before closing on a home. As the seller, if you have a failed water test, you may be required to remedy the water quality before the sale can proceed.
Failed Water Test Concerns – Water Quality Indicators
The CDC recommends you have the total coliforms and fecal coliforms tested, and the EPA’s standard for public drinking water
states that no coliform bacteria can be present. You are responsible for ensuring that your private well water is safe for consumption, and that no coliform bacteria is present. Total coliform is a class of diverse bacteria commonly found in the environment – on plants, in the soil, and in the stomachs of warm-blooded animals. Coliform is easy to detect in water and should not appear in treated water sources
Escherichia coli, or E. coli, is a fecal bacteria that is a part of the total coliform class. It can cause illness and disease. According to the “World Health Organization’s Guidelines for Drinking-Water Quality” paper , results exhibiting coliform bacteria indicate a possibility of fecal contamination in the water and should not be ignored. If your water test exhibits total coliforms present, your water is not suitable for consumption and must be treated.
The CDC list the following contaminants as a concern in private wells:

Bacteria: Campylobacter, E. Coli, Salmonella, Shigella

Chemical and Metal: Arsenic, Copper, Lead, Nitrate, Radon

Protozoa: Cryptosporidium, Giardia

Virus: Enterovirus, Hepatitis A, Norovirus, Rotavirus
How can a failed water test affect my health?
The above contaminants can cause a range of health concerns including:
- Recurring gastrointestinal illness
- Headaches
- Fatigue and weakness
- Irritability
- Respiratory distress, coughing, wheezing
- Reproductive problems
- Neurological disorders, developmental delay

Who is most susceptible to contaminated water?
- Babies, infants, and young children
- Pregnant women
- Elderly people
- Immune system compromised individuals such as
those with AIDS, undergoing chemotherapy, or
on organ transplant medications

What to do when my water test fails and comes back positive for bacteria?
Installing an appropriately sized Atlantic Ultraviolet water disinfection system will assist in getting your water back to a zero total coliform count with little maintenance. Atlantic Ultraviolet’s UV-C water purification and disinfection systems use STER-L-RAY ®
UV-C Lamps, which produce ultraviolet wavelengths lethal to virtually all bacteria, protozoa, virus, and fungi. These germicidal lamps are shortwave, low-pressure tubes that emit 95% of their ultraviolet energy at 254 nanometers, the region of germicidal effectiveness most destructive to harmful microorganisms.
Germicidal UV-C has been recognized for decades as a powerful, safe, rapid, and chemical-free water disinfection method and is listed by the CDC in A Guide to Drinking Water Treatment Technologies for Household Use as highly effective in eliminating bacteria (E. coli, Campylobacter, Salmonella, Shigella), protozoa (Cryptosporidium and Giardia), and virus (Enteric, Hepatitis A, Norovirus, Rotavirus).
Selecting an Atlantic Ultraviolet (UV-C) Water Disinfection System to Treat your Failed Water
1. Finding Your Flow Rate
The first step in selecting the appropriate Atlantic Ultraviolet water disinfection system is to find your flow rate in gallons per minute (GPM). Our water purifiers are made or assembled in the USA with peak flow in mind. We typically recommend as follows: 1 bathroom = 6 GPM, 2–4 bathrooms = 12 GPM, 5 bathrooms = 20 GPM

2. Selecting the Purifier that Fits Your GPM
Next, select a water purifier that fits your GPM and water disinfection needs. We offer a variety of different trademark lines with several models in each line. Our engineers developed the SANITRON®, MINIPURE®
, MIGHTY★PURE®
, and Bio-Logic®
Ultraviolet Water Purifiers to provide continuous, chemical-free water purification, and more importantly, peace of mind. There is no risk of overdosing, no chemical storage, and no chemical expenses. Low maintenance means these systems require occasional quartz sleeve cleaning and lamp replacement every 10,000 hours or approximately once a year.
Our Bio-Logic® Ultraviolet Water Purifiers are designed for point-of-use installation, and come in either 1.5 or 3.0 GPM. The Bio-Logic® Pure Water Pack™
includes a Bio-Logic®
1.5 GPM uv water purifier, a sediment and carbon filter, as well as an installation kit that includes tubing, a saddle valve, and long reach faucet.


Our MINIPURE® UV purifiers are designed for residential applications within the 1 to 9 GPM range. They come standard with lamp indicator lights that show lamp operation, as well as an audio alarm that alerts the user of system malfunctions.

Our MIGHTY★PURE® line is designed for residential or commercial use and ranges from 3 to 20 GPM. These units come standard with a sight port plug that safely shows UV lamp glow, as well as an integrated drain fitting that allows chamber draining without moving the unit.

Our SANITRON® ultraviolet purifiers can be used in residential, commercial, or industrial applications within the 3 to 416 GPM range. Modular units can be added or removed to change GPM as needs change over time. In addition to a sight port and drain fitting, the SANITRON®
features a patented dual-action manual wiper mechanism that cleans its quartz sleeves.

SANITRON® models S37C, S50C, and S2400C comply with NSF®/ANSI 61 and 372 — Drinking Water System Component — Health Effects and Lead Content. MIGHTY★PURE®
models MP36C (12 GPM) and MP49C (20 GPM) are available with Certification for NSF®/ANSI Standard 55 — Ultraviolet Microbiological Water Treatment Systems.
3. Consider Point-of-Entry versus a Point-of-Use
You will want to consider a point-of-entry (POE) versus a point-of-use (POU) system. POE will install before or at the water source’s entry to your home. It will provide continuous disinfection to all water plumbed downstream of the unit through your house. A POU system installs directly at the site of use—for example, under a kitchen or bathroom sink, and provides treatment only to the water coming from that treated location.
There are many optional accessories available that can either be purchased at the time of installation or installed at a later date. These accessories can help with the overall operation of your water purification system. Atlantic Ultraviolet Corporation recommends the use of our GUARDIAN™ Ultraviolet Monitor to visually indicate the level of germicidal ultraviolet purifying your water. Accessories such as the STERALERT™
, or SENTRY™
models will alert you of proper operation of your system.
Since standard and optional features vary among the different products, we suggest reviewing our Ultraviolet Water Purifier Comparison Chart or contact one of our UV Application Specialists to determine what will work best for your application. Our UV Application Specialists will help assess your GPM. They will ask you for specific information regarding why your water test failed, and for information regarding any other water treatment such as water softeners, conditioners, or filtration systems you already use. This information will make sure the Atlantic Ultraviolet water purifier they recommend will assist you in passing future water tests.

4. Disinfect the Downstream Plumbing
Once your UV-C disinfection system has been properly installed, disinfect the “downstream” plumbing between the purifier and point of use. Once the plumbing hook-ups have been made, it is a good practice to disinfect the “downstream” plumbing between the purifier and point of use. This is done by introducing chlorine or another disinfectant solution directly into the purifier chamber; 100ppm of chlorine is suggested. With the disinfectant in the purifier chamber, turn on the ultraviolet purifier. Open the “downstream” outlet until a chlorine or disinfectant odor is noticed. Close the outlet and allow the disinfectant to remain in the plumbing for at least 3 hours. Flush the plumbing with ultraviolet purified water and allow the water to run for a minimum of 5 minutes before use (to ensure no chlorine or disinfectant smell can be detected). This practice will allow the chlorine or disinfectant to be flushed through the pipes.
5. Installing a System that Fits Your Needs
Install a system that fits your water purification needs. Our Promate™ Wall-Mounting Kit will enable you to install your purifier in the correct position. SureFLO™
Flow Control Valves are optional accessories that restrict the flow of your water to the rated flow of the water purifier, offering peace of mind to ensure that the right amount of water is treated. Your Atlantic Ultraviolet UV-C water purifier will provide continuous disinfection, virtually eliminating all bacteria, virus, and fungi from the water. However, with a variety of contaminants possible in your water, your disinfection procedures could require a series of treatments to improve groundwater quality. This layered process may include particulate filtration to remove debris and turbidity, ion exchange to soften water and treat arsenic and nitrates, reverse osmosis to remove a variety of contaminants, and chemical treatment to fix hardness, PH balance, and sulfide issues. Locate your UV-C water purifier after all of the other disinfection devices to reduce the possibility of the purified water being re-contaminated by bacteria in any of these units.

How do I prevent future failed water tests?
Have a well water specialist inspection to rule out any physical issues near or with your well. The investigation can reveal bad or corroded fittings, casings, and pipes, abandoned wells nearby, or reduced water pressure. If issues are discovered with your well, you should repair them as soon as possible to mitigate continued contamination risk. If boring a new well is necessary, be sure to decommission your old well properly. Improperly decommissioned wells provide a straight path for surface contaminants to enter the aquifer, and go directly into your water well.
Install an ultraviolet water purification system from Atlantic Ultraviolet’s lineup to continuously eradicate virtually all microorganisms that have entered your water source. Made of high-quality stainless steel, the UV Water Treatment Systems from Atlantic Ultraviolet Corporation® are constructed of the highest quality materials and use germicidal ultraviolet lamps to purify water. They have many optional accessories available, giving them flexibility for virtually any application. Have your water tested annually from a certified laboratory, and more frequently if there is a reason for concern. Staying aware of your water quality enables you to take the proper precautions in treating your water.
Need help? Call Our UV Application Specialists at 1-631-273-0500, Mon.–Fri. 7am to 6pm EST.
We will help you determine the right products, and the proper installation method in order to provide the precise ultraviolet dosage for your needs.
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Our Failed Water Test Blog Posts
- What is a Failed Water Test?
- Types of Waterborne Microorganisms that can Severely Affect Your Health
- How to Choose a UV-C Purifier for Failed Water Tests
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