Chloramine Is Coming to More Fort Bend MUDs: What Changes for Your Filter
What the district notices say, and what to check before the switch
Chloramine in Fort Bend County MUD Water
The Notices Are Already Posted
If you live in one of Fort Bend County's municipal utility districts, there is a fair chance your district has posted a notice about chloramine, or will soon. Three examples from the last year and a half:
- Cinco MUD 5 posted on June 10, 2026 that "on or after June 30, 2026" its water system would change its disinfectant from chlorine to chloramine, a change it has to make before it switches to surface water. Read the notice. Cinco MUDs 7, 9, 12 and 14 posted similar notices tied to surface water from the North Fort Bend Water Authority.
- Fort Bend County MUD 162 posted on August 29, 2025 that it would begin using chloramine, with a tentative conversion date of October 3, 2025, because it is buying treated surface water from the City of Rosenberg. Read the notice.
- The North Fort Bend Water Authority, which supplies surface water to most of the MUDs and cities within its boundaries, states in its guide for pool owners that all surface water and some groundwater in Fort Bend County is treated with chloramine. Read the NFBWA guide (PDF).
A notice is a plan, not a measurement. The way to confirm a change is your district's next annual water quality report, where the disinfectant row will read "Chloramine" or "Chloramines".
Why Districts Are Switching
The short answer is subsidence. Pumping groundwater faster than it is replenished lets the land sink, which changes drainage and adds to flooding. The Fort Bend Subsidence District regulates groundwater pumping and pushes water suppliers toward alternative supplies such as treated surface water. MUD 162's notice says as much: it is buying surface water to comply with the Subsidence District's mandates to reduce groundwater pumping.
Surface water travels a long way through large pipelines before it reaches your street. The U.S. Environmental Protection Agency notes that chloramine provides longer-lasting disinfection as water moves through pipes, and that some systems switch to it to meet disinfection byproduct rules.
In our dataset of Fort Bend water systems, 39 named chloramine as their disinfectant in their 2025 water quality reports. Our chloramine by water system page lists them, with sources.
What Changes at Your Tap
Chloramine is chlorine combined with a small amount of ammonia. It is a permitted disinfectant: EPA's maximum residual disinfectant level for chloramines is 4.0 milligrams per liter, the same as for chlorine (EPA's table of drinking water regulations). The differences you notice at home are practical ones:
- It doesn't fade on its own. Free chlorine dissipates from water left standing. Chloramine doesn't do so readily, and boiling doesn't remove it effectively.
- Your filter may not keep up. Standard activated carbon, used in many pitchers and fridge filters and in whole-home tanks built for chlorine, reduces chlorine quickly and chloramine slowly.
- Fish and dialysis need it removed. Cinco MUD 5's notice warns that chloraminated water "may be toxic to fish" and that dialysis pretreatment must remove chloramine. MUD 162's notice says chloramine should be removed from water used in fish tanks, ponds and aquariums, and that both chlorine and chloramine must be removed from water used in kidney dialysis machines.
- Pools use more chlorine. The NFBWA's pool guide explains that chloraminated fill water uses up a pool's free chlorine faster than dilution alone would, so you may need to add chlorine more often.
What Changes for Your Filter
A filter that handled chlorine well can underperform the week your district switches.
- Catalytic carbon. Reducing chloramine takes catalytic carbon, an activated carbon treated so its surface breaks the chlorine–ammonia bond, plus enough contact time. In a whole-home system that means the right media in a tank sized for your peak flow, not a small cartridge.
- Check the claim, not the label. NSF/ANSI Standard 42 lists chloramine reduction as its own claim, separate from chlorine. Look for "chloramine" on the product's performance data sheet. A chlorine claim alone tells you nothing about chloramine.
- Reverse osmosis pre-filters. An under-sink RO system relies on carbon pre-filters to protect its membrane. On chloraminated water, those pre-filters need to be suited to chloramine and changed on schedule.
- Shorter media life. Chloramine uses up carbon faster than chlorine does, so replacement intervals written for chlorinated water may run short.
Read more about chloramine removal and how we size whole-home filtration for it. To ask about your own system, call 281-979-3405.
Temporary Free-Chlorine Periods
Systems that use chloramine often switch to free chlorine for a few weeks as routine maintenance of their pipes. The City of Sugar Land's main system did so from April 7 to May 5, 2026, in a notice reposted by Fort Bend County MUD 128, which buys Sugar Land water. Fort Bend County MUD 47 posted periods from October 14 to November 22, 2024 and from March 4 to May 1, 2025.
Free chlorine has a stronger smell, so unfiltered taps are more noticeable during these weeks. A filter sized for chloramine also handles free chlorine, so nothing changes for a correctly sized system. If you keep fish, use a water conditioner labeled for both chlorine and chloramine all year.
What to Do Before Your District Switches
- Find your water system. Its name is on your water bill. If it's a MUD, check the district's website for notices. New to MUDs? Read What Is a MUD?
- Check your current filter. Find its performance data sheet and look for a chloramine reduction claim.
- Protect fish and dialysis equipment. Follow your district's notice and your dialysis provider's instructions before the conversion date.
- Read the next report. Your district's annual water quality report will confirm the disinfectant and the levels it measured.
If you'd like us to check for you, call 281-979-3405 or send us your ZIP code. We'll find your water system, read its report and notices, and explain what a filter for chloramine would need in your home.
Chloramine Conversion FAQs
Does a water softener remove chloramine?
No. A softener removes hardness minerals. Chloramine needs catalytic carbon. On hard, chloraminated water the usual setup is a carbon filter followed by a water softener, with the filter first so it protects the softener resin.
Will my fridge or pitcher filter still work after the switch?
Check its performance data sheet. If it lists chloramine reduction under NSF/ANSI 42, it was tested for chloramine. If it lists only chlorine, it wasn't, and you shouldn't count on it.
What should I do about my aquarium?
Treat the water before it goes in the tank. Cinco MUD 5's notice tells fish owners to confirm that their chemicals or filters are designed for chloraminated water. Use a water conditioner labeled for chloramine.
Ready for the Switch? Talk to Fort Bend Water Pros.
Tell us your ZIP code and what you're noticing. We'll confirm your water system's disinfectant, check for posted notices, and send a quote for a filter built for it. Call 281-979-3405 or reach out online.
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