How to Shock a Well and Treat Bacteria in Well Water

Shock a well vs filter water with UV system

How to Treat Coliform, E. coli and other Bacteria in Well Water

Shock Your Well Water Using Chemicals: This is a quick, temporary solution and less expensive upfront.
Disinfection of Well Water Using Ultraviolet (UV) Light: This is a long-term, reliable, permanent solution for treating bacteria in well water.

chemical well shock vs UV water disinfection system

Iron Bacteria in Well Water

Your well water may have tested positive for coliform bacteria or iron bacteria and you're seeking a solution. Bacteria, including total coliform bacteria, iron bacteria, and E. coli are commonly found in private wells.

In fact, studies show that more than 40 percent of individual water wells are contaminated with bacteria and viruses at any given time.

If you’re one of the 19 million U.S. households on a private well, you understand that water is complicated, constantly changing, and requires regular testing.

UV Water Disinfection vs. Chlorine Shock

Key Takaways: Difference Between Chlorine Well Shock and UV Water Filtration?

Authorities like the US EPA and Health Canada recognize both chlorine chemical treatment and ultraviolet (UV) light as an effective means of disinfecting a water supply.

Chlorine Well Shock: Economical, quick fix but temporary.

UV Water Disinfection: can Long-term, reliable, and chemical-free solution.

Well Shock vs. UV Light Sterilizers

	Chlorine Well Shock	UV Water Disinfection
Temporary Fix	✔️	✔️
Long-term Solution - Can destroy 99.99% bacteria, viruses, and cysts		✔️
Easty Maintenance		✔️
24/7 Protection		✔️
Environmentally friendly - no disinfection by products and no wasted water		✔️
Indicator alarm sounds if water is not being treated		✔️
No harsh chemicals that can damage skin		✔️
No damage to well casings & pump fittings from chemicals		✔️
No dangerous gas (oxidation of organics can generate THMs, a harmful gas)		✔️
Taste and odor of water not affected		✔️

What are the Benefits of UV Water Filters?

UV light for well water provides a long-term reliable method of treating well water by running the water over a UV light that kills bacteria and viruses.
This process of exposing water to UV light is simple but effective, and destroys 99.99 percent of harmful microorganisms, including some that are chlorine resistant (such as Cryptosporidium and some forms of Giardia).
No chemicals added with UV disinfection, so there is no change to the taste or odor of your water. And, with UV, you don’t have to handle noxious chemicals, monitor the chemicals, or worry that someone in your home will become sick.
Well water treatment with a UV Treatment system (such as the Arros 15-IHS22) provides peace of mind that your well water is being treated continuously, 24/7.

Water Treatment Options - Quick Reference Guide

Step-by-step Instructions for Shocking a Well

To shock a well, follow these steps:

Turn off the power to your well pump.
Clear the area around the well head and remove the cap.
Mix the chlorine solution and pour it down the well.
Allow the solution to sit for 8-24 hours.
Flush the system by running water until the chlorine smell dissipates

Shocking or chlorinating a well may temporarily correct the bacteria problem. CAUTION: If you complete the well shocking process yourself, keep in mind that chlorine is corrosive and should be handled with care. If you’re uncomfortable handling corrosive chemicals and dealing with plumbing systems, consider calling a water treatment professional. An expert will know exactly how to solve your water issues and can also identify well issues that may contribute to repeat contamination.

With the short-term solution of treating bacteria with chemicals, how much bleach, hydrogen peroxide or chlorine is needed to shock a well will vary, depending on the depth of water well, the pH of the water, and the presence of slime or biofilm.

Is Shocking a Well Safe?

Yes, but handle chlorine with care and follow safety instructions.

If you are shocking your well because of a positive bacteria test, we recommend waiting one to two weeks and test your water again. Continue to repeat the bacteria test and take steps to shock the well until bacteria is no longer present.

What Type of Pretreatment is Required Before UV?

Since water quality has a significant impact on UV transmission, it's essential to ensure enough light can penetrate the water to effectively inactivate microorganisms.

Water quality can vary widely, so pretreatment should be customized to match the specific conditions. At a minimum, a 5-micron filter is necessary to prevent bacteria and viruses from being shielded by fine particles. If the water contains minerals like hardness, iron, or manganese, pre-treatment is recommended to avoid fouling or scaling on the quartz sleeve. Similarly, tannins (dissolved organic materials) in surface water should be treated beforehand, as they can absorb UV light and reduce its effectiveness.

What Type of Pretreatment is Required Before UV?

Is UV a Safe Way to Treat Water?

UV technology has been used for decades by municipal water suppliers and commercial water bottling plants. Because ultraviolet is safe, economical, and reliable, millions of homes and businesses now use UV technology to disinfect their water.

In fact, many municipalities are now using UV light as their PRIMARY method of disinfection and use chlorine as a secondary disinfectant to maintain low bacteria levels in distribution lines.

While most skin cancers are a result of exposure to UV rays in sunlight, the UV rays in water disinfection do NOT cause cancer. The process of exposing water to UV light to well water takes place in an enclosed stainless-steel chamber, posing no risk to family or pets.

UV disinfection is an environmentally friendly disinfection method approved by the US EPA and is a chemical-free way to disinfect and creates no byproducts.

diagram showing how water filtration equipment is set up on home with well water

Best UV Water Treatment for Well Water

Viqua VIQUA IHS22-D4 Integrated 12 GPM UV System with Sediment and Carbon with Lead Reduction Filters IHS22-D4-

Viqua VH410-F20

The VH410-F20 is an ideal water filtration system for treating harvested rainwater. The powerful 18 gpm UV system is preassembled with a 5-micron sediment filter to significantly reduces dirt, rust, sediment,

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Viqua VIQUA VH200-F10 Whole-House UV Combo System 9 gpm VH200-F10-

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VIQUA VH200-F10 UV SYSTEM

Compact, yet powerful design treats water with UV light, plus includes an
Integrated pre-filter that can remove sediment, dirt and rust for improved taste.
Includes a lamp replacement timer.
Proven UV system with premium-quality parts at a value price.
Treats up to 9 gpm, perfect for a home with 1-3 bathrooms.

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Viqua VH200 UV System

Compact, 9 gallon per minute UV water sterilizer system.
Inactivates Cryptosporidium, Giardia, E.Coli and Fecal Coliform.
Utilizes high-output lamp technology.
10-year warranty on system's UV chamber.
Treats up to 9 gpm, perfect for home with 1-3 bathrooms.

How to Know if a UV System is Working Properly?

To tell for sure if your UV system is disinfecting properly and killing all the bacteria in your water, test your water. If the test shows no bacteria, you can rest assured the UV system is doing its job. Thankfully, testing is not something you need to do every day.

UV systems generally have both audible and visual alarms to let you know if the system isn’t working properly. Some UV systems even feature a UV sensor that measures the intensity of the UV lamp, ensuring there’s a high enough UV dose to provide optimal disinfection.

You can be confident your UV Light for Well Water system is working correctly if there are no warning lights on the system and you've followed the protocol below.

System Power

Power is kept on 24/7 to treat all incoming water

Maintenance

Annual lamp change and sleeve cleaning followed

Pre-Treatment

Proper pretreatment in place to protect system

How Does UV Light for Water Filtration Work?

UV is a physical disinfection process. It gets the job done with UV-C light. In a nutshell, UV light sterilizes organisms as they pass through a stainless steel chamber of the UV system, and leaves the microorganisms unable to reproduce. If an organism cannot reproduce, the organism dies.

The preeminent method of controlling organisms in your water is at the point-of-entry into the home with a whole-home water disinfection system. When you install an ultraviolet water treatment system (such as the Arros 15-IHS22), you can be confident that the water is being treated night and day, inactivating harmful microorganisms, including cryptosporidium, giardia, E. coli, legionella, norovirus, and hepatitis A virus †.

FAQs

Does Well Water Have Chlorine?

Typically, well water does not contain chlorine. Unlike municipal water supplies, which often add chlorine to disinfect and kill harmful pathogens, well water is sourced from underground and usually untreated. Some well owners choose to add chlorine to their water systems for disinfection, especially if tests indicate bacterial contamination. But installing a UV water treatment system can effectively (and consistently) eliminate harmful bacteria, viruses, and other microorganisms that may be present in well water.

How Often Should I Shock My Well?

It depends on the level of contamination. Generally, it should be done annually or when bacteria are detected. Since you can’t see, smell, or taste bacteria in your water, you'll need to test your well water often.

With chemical shock treatments, the process will need to be repeated every time bacteria is present, understanding that even after you’ve shocked your well, re-tested, and received a clear "total coliform test", you might need to repeat this process again and again.

How Long Does It Take for a Well to Clear up After Disinfecting?

With chemical well shocking, once you’ve added the chlorine and circulated through the plumbing system, you should wait 12-24 hours before using your water.

After flushing the whole system, you should test your water again to make sure the shock was effective, and your water is free of bacteria. But keep in mind that water quality is NOT static, and it changes throughout the year – even from day to day.

With a UV system, your water is disinfected instantly, as it runs through the stainless-steel chamber. It doesn’t address the contamination in the well itself, but instead treats the water as it enters the home, destroying 99.99% of microorganisms.

How Does Well Water Become Contaminated with Bacteria?

There are many ways a water well can become contaminated with bacteria or other illness-causing microbes.

Contamination from septic systems is the biggest risk to well water.
Water levels in a well rise and fall over time, introducing new opportunities for bacterial growth.
Seasonality plays a significant role, with a general increase in well water contamination in the Spring due to thawing snow runoff.
Significant rainfall and flooding can introduce bacteria to a private well.
Manure from large-scale animal feeding operations is a threat to drinking water.
Run-off from fertilizers and pesticides is a common concern of well owners.
Poorly constructed, cracked or unsealed wells can provide a path for bacteria to enter groundwater and contaminate your well.

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