This is a newly redesigned Water-Research.net page
Page Archive

Get Informed | Elevated Chlorine and Chlorine By-Products

What is Elevated Chlorine? 

This is more commonly a problem with City Water customers that get their drinking water from a community water system or regulated system that uses chlorine to disinfect the water and maintain a disinfection chlorine residual in the water. A common problem that customers report include the following: "my water smells like a pool", the water "burns my eyes or dries my skin", or "the water tastes like chlorine". The elevated level of chlorine in the water may be an attempt by the utility or authority to manage taste, odor, and aesthetic issues and Bacterial issues within the distribution system or to disinfect a recent repair to the distribution system.

How does Elevated Chlorine become a problem? 

Elevated levels of chlorine can cause a nuisance, create irritation of the eyes and skin, damage some water treatment systems, and damage stainless-steel fixtures or appliances. Anyone who has a tank of tropical fish should know that chlorinated water can kill the fish. Chlorinated tap water should be left to stand in the open for at least overnight to give the chlorine time to leave the water before putting it in the fish tank.

What are the Health Risks for Elevated Chlorine?

The common health-related issues associated with chlorine are chronic health issues including eye irritation, dry skin, and gastrointestinal issues. Chlorine by-products like Trihalomethanes can also be a problem.

What are the Standards for Elevated Chlorine?

The EPA requires treated tap water to have a detectable level of chlorine to help prevent contamination of the water between the water source and the user. The allowable residual chlorine levels in drinking water (up to 4 parts per million) pose “no known or expected health risk with an adequate margin of safety" and most community water distribution systems have chlorine residuals ranging from 0.2 to 0.5 mg/L. A chlorine residual is maintained in the distribution system to inhibit Bacterial regrowth, prevent the creation of nuisance conditions in the distribution system, and provide a final barrier to prevent Waterborne Disease. (Source)

The Stage 1 disinfection rules provide a drinking water standard based on a total trihalomethanes concentration of 0.08 mg/L. In the 2018 Edition of the Drinking Water Standards and Health Advisories, the EPA provided guidance for the 4 Trihalomethanes. In human and animal studies, chloroform, bromodichloromethane and bromoform (all by-products of chlorination) have been linked to bladder and colon cancer; at relatively high concentrations, there is a link between trihalomethanes and birth defects, other reproductive issues, and damage to the kidneys, liver, and nervous system.

"Carcinogenicity (EPA): Chloroform, bromoform and bromodichloromethane are classified as probable human carcinogens (Class B2). Dibromochloromethane is classified as a possible human carcinogen (Class C)." (Source)  

Get Tested | Elevated Chlorine

Elevated levels of chlorine in drinking water are normally associated with a City Water supply or a private system that uses chlorine to Shock Disinfect a system or to treat a bacterial problem or as a component of a greensand filter. For City Water systems, this condition may be associated with a water main break or repair or a system attempting to manage a nuisance issue.

Level 1 | Observational Self-Testing

Level 1 Testing is done with simple observations that an individual can make with their own senses such as sight, smell, and taste. These observations can be readily apparent or can be observed as they change over time. In addition, accessible related information about the home can also be used to narrow down the cause of your water issues.

Notes on Level 1 Testing for Elevated Chlorine

All I have to say is, if it smells like chlorine, tastes like chlorine, and the water makes you think of going swimming and not getting a drink, it is likely that the issue is chlorine. For individuals who regularly use chlorinated water, chlorine can have a detectable and noticeable odor at levels of 2 mg/L and create a taste issue at 5 mg/L and individuals who are accustomed to chlorine can taste it at levels as low as 0.3 mg/L. (Source)

Level 1 | Self-Test Web App
To do a quick and easy self diagnosis of your water, click the button below.

Level 2 | Do-It-Yourself Testing

Level 2 Testing is Do-It-Yourself testing that can be done in your own home using a Testing Kit. After you’ve done Level 1 Testing, Level 2 Testing can confirm if your observations are correct. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment (see below) or continue to Level 3 Testing.

Notes on Level 2 Testing for Chlorine

There are a number of ways to screen your drinking water for the presence of chlorine.

Recommended Level 2 Tests
Recommended Products
National Testing LabsL3-NATE-W-4 | WaterCheck® Standard

<div class="product-note in-L4-sulfur-treatment">Note: Use in combination with Sulfate-Reducing Bacteria Test</div>

Crystal QuestST-CRYS-D-02 | Countertop Water Filter With Three Cartridges

<div class="product-note in-L6-bromate">Note: If the concentration is < 0.01 mg/L</div>
<div class="product-note in-L4-methyl-tertiary">Note: Concentrations < 40 ppb</div>

Crystal QuestLT-CRYS-S-01 | SMART Whole-House Water Filter System

<div class="product-note in-L6-toluene">Note: If the concentration is less than 0.8 mg/L</div>

AmazonL2-AMAZ-H-07 | Hach 5870000 Pocket Colorimeter II, Chlorine (Free and Total)

<div class="product-note in_L6-elevated-chlorine">Note: Professional</div>


Level 3 | Informational Testing

Level 3 Testing is done through an accredited Water Testing Laboratory. With Level 3 Testing, you can order a testing kit that is used to prepare your sample and submit it to the lab. By utilizing a lab, you have the assurance that a certified water expert had analyzed your water sample. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment options (see below) or continue to Level 4 Testing - Certified Testing.

Notes on Level 3 Testing for Elevated Chlorine

If you are going to test for chlorine and chlorine disinfection-by-products, there are a number of city water tests that provide a comprehensive assessment of your drinking water; you should also conduct a general test for bacteria.   Elevated chlorine is not typically associated with private water systems, but if these systems are disinfected or Shock-Disinfected, testing for chlorine by-products may be advisable.

Recommended Level 3 Tests

Level 4 | Certified Testing

A Level 4 Certified Test Test uses chain-of-custody with a water professional coming to your home to prepare the water sample and then works with an accredited laboratory in order to certify your test results. This type of testing not only gives you the highest level of assurance in the accuracy of your test results, but can also be used as a document in legal cases. For Baseline Testing, we recommend that you use Certified Testing.

Notes on Level 4 Testing for Elevated Chlorine

If you need certified testing for chlorine and chlorine by-products, it is likely that there are other intermittent water quality issues with the system. After getting general information on the source of the drinking water and understanding the "nuisance" history for this system, it is likely that the testing should include total and free chlorine, chlorine by-products, pH, conductivity, and other general water quality issues. If you need help, please Contact our team.

Get Treatment | Elevated Chlorine

This is a more common problem with City Water sources or sources that use chlorine as a disinfectant or part of a whole-house water treatment system. If there is a problem with chlorine for a well or spring, the most likely cause is a failure in an existing chlorination system, such as an erosion chlorinated or a liquid chlorine injection system, Shock Disinfection of an adjacent source, or the discharge of chlorinated water immediately upgradient or adjacent to the water source.

Short-Term Treatment

City Water - If your drinking water has a very strong chlorine odor that is causing a nuisance, we strongly recommend that you call your water supplier and report this problem. At a minimum, we suggest considering the use of some point-of-use devices to reduce the level of chlorine in the water. There are a number of faucet-mounted, shower-head-mounted, and inline Carbon Filtration systems that you may find very helpful. If you have a treatment system with a liquid chlorination feed unit or use dry-tablet chlorinates, it would be advisable to have these units inspected by a licensed professional. If there is a repeated problem, it may be necessary to install some point-of-use Carbon Filtration systems or whole-house carbon filters to reduce, but not eliminate all the chlorine (you still need to maintain a chlorine residual to prevent reinfection of the water.

Note - Chlorine is added to city water to provide a disinfection residual to control bacterial regrowth. We do not recommend removing all the chlorine from your drinking water unless it is absolutely necessary and in these cases it is likely you will need to conduct a biannual or annual Shock Disinfection and flushing of your distribution systems. When this is conducted, please remove all particle filters and by-pass any water treatment systems.

Recommended Short-Term Treatments
Contact a KnowYourH2O Recommended Professional

Not Up for A DIY? Need Help Identifying a Local Know Your H20 Team Professional? Contact Us

Long-Term Treatment

City Water Users - This is what I did at my home. We installed a particle filtration canister immediately at the city water meter (a whole-house system) and an inline carbon filter at the cold water tap (a point-of-use system) on the kitchen sink that feeds the refrigerator which has its own inline carbon block filter. With this set-up, we  filter and dechlorinate the water that we drink. This filter is typically changed as needed about every 3 to 6 months. When the city issues a boil water advisory or if the chlorine is very very high, we install a carbon block filter in the filter housing immediately after the flow meter. When the problem subsides, we remove this filter from the housing and flush the system. On an annual basis, we flush and Shock Disinfect with chlorine in a dissolved form and flush this water through the piping in the home; we also conduct an annual pasteurization of the hot-water piping. Why do we do this? We had slime bacteria living in the distribution system after moving into the home and our water supplier uses a combination of groundwater and a surface water source. In the summer months, the carbon block filters remove the odor associated with the "algae" in the surface water source.

Well and Spring Users - Most of these systems do not have continuous chlorination systems and, if they do have disinfection, the most common treatment is ozone, UV irradiation, and, in a very few cases, hydrogen peroxide. For these systems, we do recommend installing a water filter housing, without a filter, near the entry point of the home to assist with conducting a Shock Disinfection or flushing of the distribution system. For some spring systems, we have used small ozone generators and solutions of chlorine to clean the spring boxes. When a well or spring is Shock Disinfected or cleaned, we recommend the use of an NSF-approved product.

Note - Not all states permit the Shock Disinfection of water wells and please follow local laws or ordinances when discharging the highly chlorinated water. If you are shock-disinfecting a system that contains water filters or treatment systems, it is critical that the filters be removed from the housing and that any water treatment units are by-passed.

Recommended Long-Term Treatments
Contact a KnowYourH2O Recommended Professional

Not Up for A DIY? Need Help Identifying a Local Know Your H20 Team Professional? Contact Us

Archive Page Reference
This is a newly redesigned Water-Research.net page. To reference related archived Water-Research.net page(s) click the link(s) below:
No items found.