Many people in Warrenton notice a chlorine smell or taste in their tap water, especially at certain times of year. Public water systems add disinfectant to keep bacteria from growing in the pipes, so some chlorine is expected. The question for a homeowner is whether the smell is a passing nuisance or a reason to read the annual water report more closely. This guide walks through the basics so you can decide what to check next.
Why chlorine shows up in the tap
Chlorine is added as a disinfectant. As it reacts with natural organic matter in the source water, it can form disinfection byproducts. One group of these is total trihalomethanes, usually written as TTHMs. Local water reports for the Warrenton area list TTHMs among the topics they cover, so they are a reasonable thing to look up in your own report.
What a chlorine smell does and does not tell you
- A chlorine smell is a sign that disinfectant is in the water. On its own, it does not tell you the level of TTHMs.
- The smell is often stronger in water that has sat in the pipes overnight or during a warm spell.
- Hot water may smell different from cold water because the water heater and the hot line hold water for different lengths of time.
- A smell that appears suddenly, or one that comes with cloudiness, is worth reporting to the water system.
What TTHMs are
TTHMs are a group of compounds formed when disinfectant meets organic material. You cannot reliably see, smell, or taste them. A laboratory measures them, and the water system reports the results. This is why the annual report, rather than your senses, is the main source of information about them.
How to read the annual report
- Find the section on disinfectants and disinfection byproducts. The heading may use the abbreviation TTHMs.
- Note the reported result, the range of results, and the year the sample was collected.
- Look for the regulatory limit printed next to the result, and whether the report says the results met it.
- Check where the samples were taken. Results from points in the distribution system can differ from results at the treatment plant.
- Look for any notice in the report that asks customers to take action.
Simple checks at home
These checks cost nothing and help you describe the problem clearly if you contact the water system.
- If the water has sat overnight, run the cold tap for a short time before drawing water for drinking. This lets fresher water from the main reach the tap.
- Compare the kitchen tap with an outdoor hose bib or a tap farther from the water heater. Note whether the smell differs between them.
- Keep a short note of the date, the season, and what you noticed. A pattern over several weeks is more useful than a single bad day.
- Letting an open pitcher sit in the refrigerator can reduce the chlorine taste. It will not remove TTHMs.
Testing options
A home chlorine test strip or kit measures disinfectant, not TTHMs. Measuring TTHMs requires a certified laboratory. Many households in Warrenton find the fastest route is to ask the water system whether recent results are available for their area. If you want a result for your own tap, ask a certified laboratory about the test method and its reporting limit before you send a sample.
Filter choices
Activated carbon filters are commonly used to reduce chlorine taste and smell at a single tap or for the whole house. How well a filter performs depends on its certification and on the contaminants it is rated for. Read the performance data for the specific contaminant you care about, and check whether the filter has been tested for TTHMs. A filter rated for chlorine taste and odor does not automatically address every compound in the water. Change cartridges on the schedule the maker lists, because a worn cartridge can stop working well.
When to contact the water system
Call the water system office if the report is hard to follow, if the smell changes suddenly, or if you notice cloudiness, a new taste, or a notice in the mail. Ask for the most recent results for your area, the sampling schedule, and any plans to change how the water is disinfected. If the water system issues a boil water notice or a do-not-drink notice, follow the official instructions before using the tap.
This guide covers public supply only. If your home has a private well, that water is not regulated the same way, and any chlorine smell is not coming from a utility. Testing a private well is the way to learn what is in it.