# Boil Water Notice in Houston: What to Do, What Is Safe, and How to Flush Your Plumbing After It Is Lifted

*Published 2026-10-15 by Hugo Plumbing, Houston, TX.*

Houston boil water notice guide: why they happen, what to boil, what your filters and ice maker can't do, and the step-by-step flush when the notice is lifted.

Houston homeowners have learned the phrase the hard way. The freeze in February 2021 left much of the region under notices for days. In November 2022, a widely reported power failure at a city treatment plant dropped pressure across the system and put the entire city under a notice overnight. Smaller notices follow main breaks on a few streets almost every week somewhere in the metro. If you have lived here more than a couple of years, you have had a text, a push alert, or a note on the door telling you to boil your water.

The public-health part of the message is short: boil it or buy it. The plumbing part is where most people have questions. What about the ice maker? Is the fridge filter enough? Is the hot water safe? And when the notice lifts, what exactly do you flush, in what order, and what do you do when the pressure or the water color never quite comes back? This guide covers all of it, with a Houston angle throughout.

## Why Houston Issues Boil Water Notices

Public water systems in Texas operate under rules administered by the **Texas Commission on Environmental Quality (TCEQ)**. Two conditions require a boil water notice: system pressure falling below **20 psi** anywhere in the distribution system, or a known or suspected contamination risk such as a positive bacteria sample or a treatment failure.

The pressure rule is the one that catches people off guard, because low pressure does not sound like a safety problem. It is. Water mains are not perfectly sealed. They have joints, service taps, and small cracks, and under normal pressure the water pushes outward through them. When pressure collapses, groundwater and soil can seep inward instead. Nobody knows what came in, so everyone is told to boil until sampling confirms the water is clean.

In Houston, the triggers are familiar:

- **Power failures at treatment plants.** Pumps stop, pressure falls, and a citywide notice follows. This was the widely reported cause of the November 2022 notice.
- **Severe freezes.** In February 2021, burst pipes in thousands of homes and businesses drained systems faster than plants could refill them, and notices covered much of the region for days. Our [frozen and burst pipes guide](/blog/frozen-and-burst-pipes-houston-winter) covers the house side of that event.
- **Water main breaks.** A large break drops pressure in the surrounding area; the utility repairs the line, issues a notice for the affected streets, samples, and lifts it a day or two later. These are the common, small ones.
- **Storms and flooding.** Lost power at pump stations and flooded infrastructure during a hurricane can do the same thing, which is why hurricane prep checklists include stored water.

One detail that matters in this metro: the **City of Houston** is only one of hundreds of water systems here. Katy, Cypress, Spring, Pearland, Sugar Land, and most master-planned communities are served by **municipal utility districts (MUDs)** or city systems that issue their own notices with their own instructions and their own timing. A citywide Houston notice does not automatically mean your MUD is affected, and your MUD can be under a notice when Houston is not. City customers get alerts through Houston Public Works and AlertHouston; MUD customers should know how their district communicates before they need it.

## What to Boil and What Not To

The instruction is simple, and the details are where people slip.

**Boil, or use bottled water, for anything that goes in your mouth:**

- Drinking, including water for coffee makers and kettles that do not reach a full boil
- Ice, which means turning the ice maker off and throwing out what is in the bin
- Brushing teeth
- Baby formula and anything for infants
- Cooking and rinsing produce
- Water for pets

TCEQ guidance is to bring water to a **rolling boil for at least two minutes**, then let it cool. Hot water from the tap is not boiled water. Your tank or tankless water heater runs at 120 to 140 degrees, nowhere near boiling, and the water in it came from the same mains as the cold side.

**Generally fine for healthy adults, with care:**

- **Showering and bathing.** Avoid swallowing water. Small children, the elderly, and anyone with a weakened immune system may be better off with a sponge bath or bottled water for face washing, per most utility guidance.
- **Laundry.** No special precautions.
- **Dishes.** A dishwasher with a **sanitize or high-heat cycle** is fine. Hand-washed dishes should be rinsed in water with a small amount of unscented household bleach per your utility's notice, or in cooled boiled water.
- **Hand washing.** Soap and water as usual, with hand sanitizer afterward if you want extra margin.
- **Flushing toilets.** The water is fine for that. A boil notice is not a reason to stop using your plumbing.

## What a Boil Water Notice Is Not

It is **not a shut-off**. The water is still on, and you should keep using it for everything except consumption. Shutting your main valve does nothing for safety and can leave you with air in the lines when you reopen it.

It is **not a reason to drain your water heater**. Flushing the heater through its hot taps after the notice lifts is enough. Draining a tank mid-notice just means refilling it with the same water.

It is **not a reason to bypass your softener or filter**. Leave them in service. You will flush or regenerate them afterward.

And it is **not something a plumber can lift**. Hugo Plumbing does not test water for the city or the MUD and does not decide when a notice ends. What we do is fix the plumbing problems that follow a pressure event, which is the second half of this guide.

## What the Notice Means for Your Appliances and Filters

This is the part most notices gloss over.

**Refrigerator ice makers and water dispensers.** Turn them off at the start of the notice. The ice in the bin was made from suspect water; throw it out. The filter in the door or behind the kick plate is a carbon taste-and-odor filter, not a microbiological barrier.

**Pitcher filters and faucet-mount filters.** Same answer. They remove chlorine, some metals, and some chemicals. They are not rated to remove bacteria or viruses, and the water that comes out of them still needs to be boiled.

**Under-sink carbon filters.** Same. Treat the filtered tap exactly like the unfiltered one.

**Reverse osmosis systems.** An RO membrane removes far more than carbon does, and some systems are certified for microbiological purification. Most are not, and utilities say not to rely on RO during a notice unless the manufacturer specifically certifies it for that use. If you are not certain, boil. Our [water softener vs whole-house filter](/blog/water-softener-vs-whole-house-filter-houston) guide covers what each type of equipment actually does.

**Water softeners.** A softener exchanges hardness minerals for sodium. It does nothing for bacteria. Leave it running.

**Tankless water heaters.** The hot water is not boiled water, and a pressure drop can let sediment reach the heat exchanger's inlet screen. If flow on the hot side is weak after the event, that screen is the first thing to check. A tankless flush covers the maintenance side.

**Tank water heaters.** The tank will have collected whatever sediment the refill pushed through the mains. It settles, and the tank will tell you about it later by popping and rumbling. More on that below.

## After the Notice Is Lifted: The Flush

Your utility's lifted-notice message will include flushing instructions and times. Follow those first, because they are written for the actual event and the actual system. What follows is the sequence most Houston utilities and plumbers recommend, in the order that gets clean water to every fixture fastest.

1. **Start at the cold tap nearest your main shutoff.** Usually a hose bib or the laundry room. Open it fully and let it run for several minutes, or for the time your utility specifies. If you do not know where the main enters, our [how to shut off your water main](/blog/how-to-shut-off-your-water-main-houston) guide shows where it is on most Houston homes.
2. **Work through every cold tap in the house**, including bathtubs, showers, outdoor spigots, and the laundry supply. A few minutes each, moving away from the main. Remove aerators first if you can, so debris does not clog them.
3. **Flush the hot taps.** Run each hot tap until the water runs hot and then a few minutes longer. This pulls fresh water through the water heater. You do not need to drain the tank.
4. **Flush every toilet** two or three times.
5. **Ice maker.** Turn it back on, dump the first two or three bins of ice, then let it make a bin you keep.
6. **Refrigerator water line.** Dispense water for a couple of minutes to flush the line, then **replace the filter**. The old one has suspect water sitting in it.
7. **Point-of-use filters.** Replace pitcher, faucet-mount, and under-sink cartridges. Flush an RO system per the manufacturer, which usually means draining the storage tank and letting it refill once or twice, then replacing the pre-filters.
8. **Dishwasher.** Run one empty cycle on hot.
9. **Washing machine.** Run one empty cycle on hot.
10. **Faucet aerators and showerheads.** Unscrew, rinse out grit, soak in vinegar if there is scale, and reinstall.
11. **Water softener.** Start a manual regeneration cycle. Check the manual for how.
12. **Whole-house filter.** Replace the cartridge or run a backwash, per the manufacturer.
13. **Humidifiers, CPAP machines, and anything else that holds water.** Empty, clean, and refill with fresh water.

If the water runs cloudy, yellow, or brown during the flush, keep going. That is sediment stirred up by the pressure change, and it usually clears in a few minutes. If it does not clear after a thorough flush, our [brown, yellow, or cloudy water](/blog/brown-yellow-or-cloudy-water-houston) guide covers what else it can be.

## The Plumbing Problems That Show Up Afterward

A pressure collapse and refill is hard on a plumbing system. The water that comes back in carries sediment, rust, and air, and it arrives in a surge. Here is what we see in the week after a notice, and what to do about each.

**Pressure that never comes back.** The utility says pressure is restored, but your house is weak at every fixture. Two suspects. A **pressure reducing valve (PRV)** can jam with debris or fail outright after a pressure swing; see our [PRV replacement cost guide](/blog/pressure-reducing-valve-replacement-cost-houston). Or a weak spot in your own line let go when pressure returned, and you now have a leak, which a [leak detection](/services/leak-detection) visit will find. If only some fixtures are weak, the cause is usually clogged aerators or a cartridge, covered in our [low water pressure in Houston](/blog/low-water-pressure-in-houston-causes-and-fixes) guide.

**Clogged aerators and showerheads.** Grit from the refill lodges in the screens. Unscrew and rinse. If the flow stays poor on one faucet, the cartridge may have caught debris, which is a faucet repair visit rather than a replacement in most cases.

**Toilets that run or refill on their own.** A grain of sand in a fill valve or on a flapper seat is enough to keep a toilet trickling. Sometimes a few flushes clears it. If not, the fill valve needs cleaning or replacement; our [running toilet guide](/blog/running-toilet-causes-and-fixes) walks through it, and a toilet repair visit is quick when it does not.

**Water heater popping, rumbling, or running out of hot water sooner.** The refill pushed sediment into the tank, where it settled on the bottom and now sits between the burner and the water. The noise is water boiling under the sediment layer. A tank flush fixes it, and it is the main item in a [water heater maintenance](/services/water-heater-maintenance) visit. Our [water heater noise guide](/blog/water-heater-making-noise-popping-rumbling) explains the sounds. A heater that was already old and heavily scaled sometimes starts leaking after this kind of event, and that is a water heater repair or replacement conversation.

**Banging pipes when fixtures shut off.** Air in the lines from the refill, or a water hammer arrestor that lost its charge during the pressure swing. Flushing usually purges the air. If the bang persists, see [water hammer and banging pipes](/blog/water-hammer-banging-pipes-houston).

**Discolored water that will not clear.** Sediment from the mains should flush out in minutes. If a yellow or brown tint persists for days, especially on the hot side only, the cause is inside your house, usually a corroding water heater tank or old galvanized pipe, and it needs a look.

**No water at all.** Rare after a notice, but if the utility has restored service and you have nothing, check your main valve and your PRV before anything else. Our [no water in the house](/blog/no-water-in-house-what-to-do-houston) guide covers the sequence.

## When to Wait and When to Call

**Wait and flush** if the water is discolored for the first few minutes, pressure is a little low on the first day while the system refills, a toilet runs once or twice and stops, or the pipes bang a few times while air works out.

**Call a plumber** if pressure is still low after the utility says it is restored, discolored water persists after a full flush, a toilet keeps running, a faucet keeps dripping after you cleaned the aerator, the water heater starts popping or leaking, or the pipes keep hammering. Each of these is a small part that caught debris or a pressure swing, and each gets more expensive the longer it runs.

Hugo Plumbing's diagnosis visit is free, with no trip or service fee, and every repair is quoted as one flat written price before the work starts. Our work carries at least a one-year warranty with extended coverage by job type, and we have Spanish-speaking technicians available. If the pressure event left you with a leak or a failed heater, the [24/7 emergency line](/services/emergency-plumbing) is (713) 409-7176, call or text. If you want the whole system looked over after a rough week, a plumbing inspection checks the PRV, the heater, the valves, and the fixtures in one visit.

## Frequently Asked Questions

**Why does Houston issue boil water notices?**

Texas rules administered by the Texas Commission on Environmental Quality require a public water system to issue a boil water notice when pressure drops below 20 psi anywhere in the system or when there is a known or suspected contamination risk. Low pressure matters because it can let groundwater or soil seep into the pipes through small cracks and joints. In Houston the triggers are usually a power failure at a treatment plant, a severe freeze that bursts lines and drains the system, or a large water main break. Small notices for a few streets after a main repair are common and often go unnoticed.

**Can I shower or do laundry during a boil water notice in Houston?**

For most healthy adults, yes. Utilities generally advise that showering, bathing, and laundry are fine as long as you do not swallow the water, with extra care for small children and anyone with a weakened immune system, who may be better off with a sponge bath. Boiling is for anything that goes in your mouth: drinking, ice, brushing teeth, baby formula, cooking, washing produce, and water for pets. Dishes are safe in a dishwasher with a sanitize or high-heat cycle, or washed by hand and then rinsed in water with a small amount of unscented bleach, per your utility's instructions.

**Does my refrigerator filter or reverse osmosis system make the water safe during a boil water notice?**

Treat it as no. Refrigerator filters, pitcher filters, and most under-sink carbon filters are designed to improve taste and remove chlorine and some contaminants, not to remove bacteria or viruses, so the water that comes out of them still needs to be boiled. A reverse osmosis system removes more, but utilities and most manufacturers still say not to rely on it during a notice unless the manufacturer specifically certifies it for microbiological purification. Turn off the ice maker and water dispenser for the duration and plan to replace the filter afterward.

**What should I do after a boil water notice is lifted?**

Follow the flushing instructions in your utility's lifted-notice message first, because the timing varies. The usual sequence is to run every cold tap starting with the one nearest your main shutoff for several minutes each, then the hot taps, then dump and remake ice two or three times, flush the refrigerator water line and replace its filter, replace any point-of-use filters, run the dishwasher and washing machine empty on hot, clean faucet aerators, and manually regenerate a water softener or flush a whole-house filter per the manufacturer. Hot water from the tap was never boiled water, so the heater gets flushed through its taps too.

**Do I need a plumber after a boil water notice?**

Usually not, but a pressure event stirs up sediment and can damage small parts. Call a plumber if the pressure never comes back to normal after the utility says it should, if discolored water does not clear after a thorough flush, if a toilet starts running or a faucet drips after debris reaches the fill valve or cartridge, if the water heater starts popping or rumbling, or if the pipes bang when fixtures shut off. Hugo Plumbing's diagnosis visit is free, and the repair is quoted as one flat written price before any work starts.

If the notice lifted but your plumbing didn't recover, call Hugo.

## Frequently Asked Questions

### Why does Houston issue boil water notices?

Texas rules administered by the Texas Commission on Environmental Quality require a public water system to issue a boil water notice when pressure drops below 20 psi anywhere in the system or when there is a known or suspected contamination risk. Low pressure matters because it can let groundwater or soil seep into the pipes through small cracks and joints. In Houston the triggers are usually a power failure at a treatment plant, a severe freeze that bursts lines and drains the system, or a large water main break. Small notices for a few streets after a main repair are common and often go unnoticed.

### Can I shower or do laundry during a boil water notice in Houston?

For most healthy adults, yes. Utilities generally advise that showering, bathing, and laundry are fine as long as you do not swallow the water, with extra care for small children and anyone with a weakened immune system, who may be better off with a sponge bath. Boiling is for anything that goes in your mouth: drinking, ice, brushing teeth, baby formula, cooking, washing produce, and water for pets. Dishes are safe in a dishwasher with a sanitize or high-heat cycle, or washed by hand and then rinsed in water with a small amount of unscented bleach, per your utility's instructions.

### Does my refrigerator filter or reverse osmosis system make the water safe during a boil water notice?

Treat it as no. Refrigerator filters, pitcher filters, and most under-sink carbon filters are designed to improve taste and remove chlorine and some contaminants, not to remove bacteria or viruses, so the water that comes out of them still needs to be boiled. A reverse osmosis system removes more, but utilities and most manufacturers still say not to rely on it during a notice unless the manufacturer specifically certifies it for microbiological purification. Turn off the ice maker and water dispenser for the duration and plan to replace the filter afterward.

### What should I do after a boil water notice is lifted?

Follow the flushing instructions in your utility's lifted-notice message first, because the timing varies. The usual sequence is to run every cold tap starting with the one nearest your main shutoff for several minutes each, then the hot taps, then dump and remake ice two or three times, flush the refrigerator water line and replace its filter, replace any point-of-use filters, run the dishwasher and washing machine empty on hot, clean faucet aerators, and manually regenerate a water softener or flush a whole-house filter per the manufacturer. Hot water from the tap was never boiled water, so the heater gets flushed through its taps too.

### Do I need a plumber after a boil water notice?

Usually not, but a pressure event stirs up sediment and can damage small parts. Call a plumber if the pressure never comes back to normal after the utility says it should, if discolored water does not clear after a thorough flush, if a toilet starts running or a faucet drips after debris reaches the fill valve or cartridge, if the water heater starts popping or rumbling, or if the pipes bang when fixtures shut off. Hugo Plumbing's diagnosis visit is free, and the repair is quoted as one flat written price before any work starts.

## About the Author

Hugo Plumbing is a licensed, insured, family-run plumbing company in Houston, Texas providing residential and commercial plumbing repair, replacement, and installation, with 24/7 emergency service. Services: https://hugoplumbingtx.com/services · Book: https://book.housecallpro.com/book/Hugo-Plumbing/a36279ec67c14456b0b25f1f992b2f4e?v2=true · Call: (713) 409-7176

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