Rockville, Maryland Water Outage Today
Live Rockville water outage reports, City of Rockville Water’s emergency line and the system’s federal record.
Weather data by Open-Meteo.com
No water outage reports in Rockville, Maryland in the last 24 hours
Who supplies water in Rockville?
Rockville is served by more than one water system: City of Rockville Water, WSSC Water. Which one serves your address depends on the neighborhood, and the name on your water bill is the one to call about an outage.
Public water systems in Maryland are regulated by the Maryland Department of the Environment (MDE).
To report no water or a main break, call City of Rockville Water at 240-314-8567, or WSSC Water at 301-206-4002.
Rockville water system at a glance
Federal records name City of Rockville as the public water system for Rockville, with about 52,000 people on its mains. Customers know it as City of Rockville Water; the name on your bill is the one to call.
| Item | Detail |
|---|---|
| Water system in EPA records | City of Rockville (MD0150003) |
| Run by | Local government |
| People served | 52,000 through 17,500 service connections |
| Source of the water | Surface water (rivers, lakes or reservoirs) |
| Active facilities listed by EPA | 1 surface intake, 1 treatment point, 1 storage tank or reservoir |
| Connections to other systems | 1 (1 listed as emergency supply) |
| State regulator | Maryland Department of the Environment (MDE) |
| Health-based violations since 2015 | 0 |
| Highest lead result (90th percentile) | 0 ppb, action level 15 ppb |
Source: EPA SDWIS (Safe Drinking Water Information System).
Source water and treatment in Rockville
Rockville drinks surface water. City of Rockville draws it from the Potomac River and treats it before it goes into the distribution system. Treatment points named in EPA's facility list include Potomac Filter Plant. After treatment the water is held in 1 storage tank or reservoir, which is the buffer that keeps taps running for a few hours after a pump or main fails.
The outage angle. Because the water is drawn from open surface sources, it has to be filtered and disinfected continuously. A plant problem therefore hits everyone at once, unlike a main break, which only dries up the blocks on either side of the damaged pipe. EPA lists 1 emergency connection to neighboring systems, which can be opened to move water across a boundary during a failure.
Why the water goes out in Rockville
These are the causes that match the record for Rockville, listed roughly in order of how much they matter here.
- Freezing weather. Rockville sees about 83 days a year with a low at or below 32°F, and 14 days at or below 20°F. The coldest morning in the 2015 through 2025 record came on February 20, 2015. The longest stretch with highs that never rose above freezing ran 12 days, ending January 7, 2018. Frost pushes into shallow service lines first. Mains follow when the ground heaves and thaws, which is why break counts climb a day or two after the temperature swings.
- Flooding and heavy rain. NOAA logged 310 flood, flash flood and heavy rain reports in Montgomery County from 2015 through 2026, and 8 days a year bring an inch of rain or more. High water can wash out the ground under buried pipe, flood pump stations and push treatment plants past their limits, which is why boil notices so often follow a flood.
- Storm-driven power loss. Thunderstorm wind, hail and tornado reports in Montgomery County number 561 since 2015. Pump stations and treatment plants that depend on Pepco run on the electric grid, so a storm that downs power lines can lower water pressure even when no pipe is damaged.
- Long dry spells. The longest stretch without measurable rain since 2015 lasted 38 days, ending November 9, 2024. Dry soil shrinks and shifts around buried pipe, and breaks often cluster when the rain returns and the ground swells again.
- Digging and utility work. Street projects, fiber installation and excavation near buried pipe regularly cut mains in Rockville with no warning, usually on a day with perfectly ordinary weather.
- One-address problems. A closed valve, a meter swap or a failed regulator can leave a single house dry. Compare notes with a neighbor first; if they have water too, start with your own plumbing.
How weather strains the Rockville water system
Main break season in Rockville runs from late fall into early spring, with the coldest stretch around December through February.
| Measure | Value |
|---|---|
| Days a year at or below 32°F | 83.4 |
| Days a year at or below 20°F | 13.8 |
| Days a year with a high at or below 32°F | 9.9 |
| Days a year at or above 95°F | 7.9 |
| Days a year at or above 100°F | 0.2 |
| Days a year with an inch of rain or more | 7.7 |
| Average annual precipitation | 43.3 in |
| Wettest year | 2018 (67 in) |
| Driest year | 2025 (35.5 in) |
| Coldest day in the record | February 20, 2015 |
| Hottest day in the record | July 16, 2024 |
Source: NASA POWER daily reanalysis (MERRA-2) for the city center, 2015–2025.
Freezing days peak in January, averaging 24 a year. Source: NASA POWER reanalysis, 2015–2025.
The wettest year was 2018 with 67 inches; the driest was 2025 with 35.5. Source: NASA POWER reanalysis, 2015–2025.
A note on the numbers: they are modeled for the city center and averaged over eleven years, so they show how often Rockville sees each kind of weather, not what any one thermometer read on a given day.
Is Rockville water safe? Boil notices and EPA record
Since 2015, EPA's record for City of Rockville shows no health-based violations. It also lists 17 monitoring or reporting entries that are about paperwork rather than water quality, such as a missed sample or a late report.
Most recent entries, all monitoring or reporting:
- July 2025: A lead and copper violation It is marked resolved.
- July 2023: A missed or late monitoring or reporting requirement (chemical and radiological contaminants) It is marked resolved.
| Type of violation | Health-based | Monitoring and other |
|---|---|---|
| Chemical and radiological contaminants | 0 | 15 |
| Other | 0 | 1 |
| Lead and copper | 0 | 1 |
Source: EPA SDWIS.
Monitoring and other Health-based
Violations are counted by the year the compliance period began. Source: EPA SDWIS.
When Rockville loses pressure after a break or a failed test, City of Rockville Water asks affected customers to boil water for drinking and cooking. The notice ends only after samples come back clean, which usually takes one to two days after service returns, and the Maryland Department of the Environment (MDE) supervises the process.
Lead service lines and old plumbing in Rockville
The most recent 90th-percentile lead result filed for City of Rockville is 0 ppb (2018). The federal action level is 15 ppb, so that result is far from the limit.
Highest result on file: 0 ppb. Source: EPA SDWIS.
35.6% of occupied homes in Rockville were built before 1970, and lead service lines and solder stayed legal until the federal ban in 1986. After any outage that disturbs the pipes, run the cold tap 30 seconds to 2 minutes before drinking, and ask City of Rockville Water about its lead service line inventory.
When will the water come back on in Rockville?
A crew that arrives at an ordinary main break in Rockville usually needs 4 to 8 hours to isolate the pipe, dig, repair, flush and restore pressure. Large transmission mains, deep pipes and breaks under busy streets can take a day or more.
| Situation | Typical time |
|---|---|
| Planned shutoff | The posted window, though crews often finish ahead of it |
| Ordinary main break | Roughly 4 to 8 working hours |
| Large or deep main | 1 to 3 days |
| Low pressure after a pump or power failure | Until power returns and tanks recover, often within a day |
| Boil water notice after service returns | About 24 to 48 hours, until lab tests are clean |
| Frozen service line or meter | Until it thaws or a plumber repairs it |
Source: Utility practice, EPA and state boil water guidance.
Ask City of Rockville Water for a restoration estimate when you report the outage; for large breaks it is normally posted and updated as the repair progresses.
Preparing for a long water outage in Rockville
Census figures put the typical Rockville household at about 2.5 people. At one gallon per person per day that is 8 gallons for three days or 35 gallons for a two-week supply.
- 33.2% of homes are in buildings with 20 or more units. Upper floors lose pressure first, and rooftop tanks and booster pumps depend on building power.
- A standard water heater is a ready-made 40-gallon reserve. Shut off its power or gas, open a hot tap somewhere in the house, and draw from the drain valve.
- Fill the bathtub and a few large pots as soon as you hear a break is likely; that water is for flushing and washing, not drinking.
Rockville versus neighboring water utilities
| City | System | People served | Source | Health violations since 2015 | Highest lead (ppb) |
|---|---|---|---|---|---|
| Rockville, MD | City of Rockville | 52,000 | Surface | 0 | 0 |
| Gaithersburg, MD | Washington Suburban Sanitary Commission | 1,900,000 | Surface | 0 | 1.1 |
| Alexandria, VA | City of Alexandria | 159,200 | Bought (surface) | 0 | 0.5 |
| Bowie, MD | Washington Suburban Sanitary Commission | 1,900,000 | Surface | 0 | 1.1 |
| Frederick, MD | City of Frederick | 54,000 | Surface | 0 | 1.1 |
Source: EPA SDWIS.
Water outage pages for nearby cities
Gaithersburg, MD · Alexandria, VA · Bowie, MD · Frederick, MD
Staying informed about water service in Rockville
Sign up for alerts from City of Rockville Water and check its website or social accounts when the water goes off. If a boil advisory is issued, the water outage guide covers how to treat water and when it is safe again.
Rockville frequently asked water questions
Who do I call about no water in Rockville?
City of Rockville Water at 240-314-8567, day or night. Use 911 only if a main break is flooding property or roads.
Where does Rockville get its water?
Surface water supplies Rockville, according to EPA records for City of Rockville. It draws from the Potomac River.
Can you drink the tap water in Rockville?
EPA lists no health-based violations for City of Rockville since 2015, and its latest 90th-percentile lead result is 0 ppb against the 15 ppb action level. After a boil water notice, follow it until the utility lifts it.
What time of year are Rockville water main breaks most common?
Breaks in Rockville pile up in the cold, with about 83 freezing days a year and the worst stretch from December to February. The days right after a deep freeze, when the soil thaws and shifts, are usually the busiest.
What causes low water pressure in Rockville?
A sudden drop usually means a break or valve problem nearby, while a slow decline in the evening points to demand. If the whole street is affected, tell City of Rockville Water; if not, look at your own regulator and shutoff.
When will a boil water notice be lifted in Rockville?
Usually 24 to 48 hours after pressure is restored. The utility has to collect samples, wait for the lab to confirm there is no bacteria, and then announce the all-clear. City of Rockville Water posts notices and lifts them; the Maryland Department of the Environment (MDE) oversees the process.
How many gallons of emergency water does a Rockville family need?
Store at least three days of water, and two weeks if you can. With about 2.5 people in a typical Rockville home, that is roughly 8 and 35 gallons.
Should I worry about lead in Rockville water?
Lead pipe was legal until 1986, and 35.6% of occupied homes in Rockville predate 1970, so it is possible in older neighborhoods. City of Rockville Water can tell you what your service line is made of; a lead-certified filter is a sensible precaution if you are unsure.
Where can I see water outages in Rockville?
There is no pipe-level map on this site. The report counter above reflects what residents of Rockville have sent in over the last day, and City of Rockville Water has the official word on main breaks, planned shutoffs and boil notices.
More outage pages for Rockville and nearby
Other outage types in Rockville
Water Service Outages in cities near Rockville
- Gaithersburg, MD 5 mi · WSSC Water
- Alexandria, VA 20 mi · Virginia American Water
- Bowie, MD 25 mi · WSSC Water
- Frederick, MD 27 mi · City of Frederick Department of Public Works
- Baltimore, MD 32 mi · Baltimore City Department of Public Works
- Lancaster, PA 80 mi · City of Lancaster Water Bureau
Report counts are user-submitted; other figures name their official source. How our data works
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