A water main break near Michigan Street flooded a Grand Terrace neighborhood on August 27, 2025, and it was not the first. This post uses both breaks to explain what a homeowner can do when street water heads for a yard or a door, who serves the water and sewer system, and how a crew handles a house that took on water from outside.
Key takeaways
- On August 27, 2025, a major water main broke near Michigan and Main streets about 10:30 p.m. and flooded a neighborhood and at least one home.
- Residents said 5 to 10 inches of water covered Michigan Street at the height of the break.
- On June 17, 2015, an 18 inch main ruptured at Barton Road and Michigan Street next to Grand Terrace Elementary School and created a sinkhole.
- Riverside Highland Water Company serves Grand Terrace and the adjacent community of Highgrove, and the city owns and operates its sanitary sewer system.
- Street water that enters a house is treated as contaminated, so wet porous materials are usually removed.
The August 2025 break near Michigan and Main
A major water main broke at about 10:30 p.m. on August 27, 2025, near Michigan and Main streets. The water flooded a neighborhood and at least one home.
Residents said 5 to 10 inches of water covered Michigan Street at the height of the break. That is enough to reach a garage door, a doorstep or a low window.
Neighbors described water moving along the street and into yards, and one household found it inside the home. A rise of 5 to 10 inches on pavement can push through a garage door seal or over a low threshold without warning.
- The break happened at night, when people were home and often asleep
- The water came from a pressurized main, so it arrived fast
- At least one home took on water, which shows the street flow can enter a house
- The event shows why a family should know where its main shutoff is
The June 2015 break at Barton Road
On the night of June 17, 2015, an 18 inch water main ruptured at Barton Road and Michigan Street next to Grand Terrace Elementary School. The break created a sinkhole.
Water from that break ran down Barton Road. Two main breaks near the same intersection, years apart, are a reminder that aging public systems fail on their own schedule.
A sinkhole next to a school also shows how much soil a broken main can move. For a homeowner, the lesson is to keep a clear path away from the street and to stay out of the area until the utility confirms it is safe.
Who serves water and sewer in Grand Terrace
Riverside Highland Water Company is a private water company that serves Grand Terrace and the adjacent community of Highgrove. The sanitary sewer system is owned and operated by the City of Grand Terrace.
Wastewater is treated at the Colton Regional Wastewater Treatment Facility under an agreement between Grand Terrace and the City of Colton. Storm drains are maintained by the city.
This post does not say which party handles a particular break, and homeowners should confirm with their water provider.
The sewer and the water system are separate. A break in the water main does not mean a sewer backup, but a house that has both problems needs two different kinds of cleanup.
What to do when street water heads for the house
The first priority is to keep people safe and keep water out where possible.
Sandbags, towels and a wet vacuum can slow water at a doorway, but none of them replaces a proper extraction once water is inside.
Pets and children are drawn to puddles, so keep them away from standing water that may have run across roads and driveways.
- Stay out of moving water and away from the sinkhole edges or damaged pavement.
- Turn off power to wet areas at the panel if it can be reached dry.
- Photograph the water level, the street and any damage to the yard or garage.
- Move valuables and electronics to higher ground.
- Report the water to the water provider and note the time of the report.
- Keep children and pets out of the wet rooms.
Do not wait for the street to dry
A house can look fine once the street clears while water sits in the carpet, under cabinets or in the wall bottoms. Extraction soon after the water stops limits how far it wicks.
How a crew handles a house that took on street water
Water from a main break starts as clean drinking water, but it gathers soil, road debris and whatever else is on the ground as it crosses the street. By the time it enters a house, it is usually treated as contaminated.
Water extraction comes first, using truck mounted units and portable extractors. Wet carpet and pad are removed, drywall is cut above the wicking, and the rest is cleaned and dried.
Extraction and removal
Standing water is pulled, silt and debris are bagged, and the crew moves to wall bottoms and cabinet bases to check for hidden moisture.
Rooms with hardwood or laminate are checked early, because water can get under planks and cause cupping that is easy to miss from above.
Drying the structure
Air movers and dehumidifiers run until readings in the framing and slab return to normal. The crew logs those readings at each visit.
Pipe failures after pressure comes back
A break in the street can lead to a second problem inside the house. When pressure drops and returns, weak fittings, old hoses and supply pipes can leak or fail.
If water starts running in a wall or under a sink after service is restored, a burst pipe water damage job may follow. Shutting the house main and calling a plumber stops the second loss.
The Highland page for extraction explains the same process used across the area.
A pressure change can also loosen sediment in older pipes and cause discolored water for a short time. That is not a leak, but a plumber can confirm that fittings and hoses are sound.
Records, neighbors and the city
Neighbors on the same street are often affected by the same break. Comparing notes helps document the event, but each household's loss is its own.
Dated photos, the time of the break and the restoration team's moisture readings support an insurance claim. The Grand Terrace page lists the services crews offer in the city.
A written account of the event, even a short one in a phone note, makes the claim easier to explain. It should list when the water was first noticed and when it stopped.
Questions
When did the major Grand Terrace main break happen?
A major water main broke at about 10:30 p.m. on August 27, 2025, near Michigan and Main streets.
How deep did the water get on Michigan Street?
Residents said 5 to 10 inches of water covered Michigan Street at the height of the August 2025 break.
Was there an earlier break?
Yes. On June 17, 2015, an 18 inch main ruptured at Barton Road and Michigan Street next to Grand Terrace Elementary School and created a sinkhole.
Who provides water in Grand Terrace?
Riverside Highland Water Company, a private company, serves Grand Terrace and the adjacent community of Highgrove.
Is main break water cleaned like a plumbing leak?
Not exactly. It gathers soil and debris from the street, so wet porous materials are usually removed and surfaces are cleaned and dried.
What should a household do about a flooded yard that has not reached the house?
Photograph it, keep the doors closed, move items off the floor near entrances and report it to the water provider. If water reaches the house, call for extraction.