Heavy rainfall puts more water into the sanitary sewer system than it can carry away. That extra volume builds pressure, and wastewater comes back through the lowest drains in the house instead of flowing out normally.
In Gilbert, that usually means a laundry or garage floor drain, a utility sink, a walk-in shower or a ground-floor toilet. Not a basement drain. Most homes here are on slabs. The problem sits in your own sewer lateral, the public main, or both.
Evolution Plumbing handles sewer backups across Gilbert, Chandler, Mesa and the wider Valley with same-day response, plus planned sewer camera inspections, hydro jetting and backwater-valve work before monsoon season.
If water is already coming up through a drain, stop using water and call us at (480) 662-6555.
Key Takeaways
- Rain adds water to a sewer that’s already carrying wastewater. It doesn’t create the sewage, but if your lateral or the main is already short on capacity, a monsoon burst can push it into a backup.
- Two or more fixtures gurgling together points downstream of both, usually the main line or lateral, not one trap.
- Only your house backing up means the lateral is the likely cause. Several houses on the street backing up together points to the Town main.
- EPA still cites an estimate of 23,000 to 75,000 sanitary sewer overflows a year nationwide. It’s an older national figure and excludes indoor backups, but it’s still what the agency publishes.
- Had a previous backup, an older clay or cast iron lateral, or roots cleared before? Book a camera inspection before monsoon season.
- Standard homeowners policies exclude sewer backup damage unless you’ve added water-backup coverage, and that endorsement covers interior damage, not the buried lateral itself.
What’s Actually Happening In Your Line
Your private sewer line runs from your house to the public main. That’s where we start, because it’s the side we can inspect and fix. In Gilbert, the property owner is generally responsible for that line, so it’s worth confirming where your tap actually sits before paying for any excavation near the street.
During heavy rain, groundwater and surface water get into the sanitary system through cracks, failed joints and damaged cleanouts. This is called infiltration and inflow, or I/I. A sanitary sewer isn’t built to carry stormwater, so once enough extra water gets in, capacity drops and wastewater gets pushed back toward the lowest opening in the house.
Older clay and cast iron laterals are more vulnerable to tree root intrusion and joint failure. PVC became standard through the 1970s and 1980s, so most newer Gilbert homes are on plastic, lower-risk but not trouble-free. Valley soils like caliche can shed intense monsoon rain rather than absorbing it, so water can pond over a damaged lateral and find its way in through open joints.
Roof runoff shouldn’t be part of this. Gilbert has adopted the 2018 International Plumbing Code, which prohibits draining stormwater into a sanitary sewer, though improper connections do turn up in older or altered properties. A camera won’t always confirm whether a downspout or another stormwater source connects further upstream. If we suspect a cross-connection, dye testing is the better way to check it. If your outside cleanout already holds water on a dry day, the line has a problem regardless of the weather.
Signs Your Sewer Is Backing Up
Gurgling is the clearest early warning. One noisy fixture can be a local clog. Two or more gurgling together means the restriction is farther down the shared line, and that’s when it’s worth booking a camera rather than reaching for a plunger.
A sewage odor indoors can mean a trap has run dry or a pressure change is letting gas through. Floor drains and other traps hold water that normally blocks sewer gas, so a returning smell is worth investigating rather than covering up.
Water rising through a floor drain, utility sink or shower while it’s raining is an active backup. Stop using water throughout the house and call us.
Outside, a soggy patch or unusually green strip along the lateral route can point to a leak. In our dry climate, ground that stays damp between storms is worth putting a camera on. And if slow drains get dramatically worse during a storm and recover afterward, rain-related loading is part of the problem even if everything seems fine again the next morning.
What To Do If It’s Already Backing Up
Stop using water. All of it. Every tap off, no more flushing, and stop the dishwasher or washing machine if they’re running.
Treat the water as contaminated. Keep children and pets away, avoid bare-skin contact, and use gloves and boots if you need to get near it. If water has reached outlets or appliances, only switch off the affected circuit if you can reach the breaker panel without standing in water.
Photograph the damage before cleanup, wide shots of the room plus close-ups of water levels and affected belongings. Check your homeowners policy while help is on the way. Standard cover usually excludes sewer backup unless you’ve added a water-backup endorsement, and that endorsement covers interior damage, not the buried lateral itself, which needs separate service-line coverage.
Don’t plunge every drain and don’t pour drain cleaner down the line. When several fixtures are backing up together, the problem is farther downstream than one trap can fix, and it needs professional drain cleaning rather than a bottle from under the sink.
If several houses on the street are affected, call the Town’s Public Works rather than us. If it’s just your house, we provide same-day response across Gilbert, Chandler, Mesa and the wider Valley.
How To Prevent The Next Backup
We put a camera in the line first, always, before recommending a repair. If the pipe is sound but narrowed by grease, sediment or root hair, hydro jetting clears it and restores usable diameter, though roots can return on clay and cast iron, so jetting may be maintenance rather than a one-time fix.
If the line itself is serviceable and the problem is reverse flow from a surcharged main, a backwater valve is worth talking about. It sits in the lateral, opens for outgoing wastewater and closes against flow coming back from the street. It isn’t a fix for a half-blocked pipe, and it needs the flap opened, inspected and cleaned at least once a year. Check for an existing round access lid in the yard or garage slab before pricing a new one.
Sump pumps are uncommon in Gilbert since most homes are slab-on-grade, but some custom homes, sunken garages and below-grade rooms have them. If yours does, test it before monsoon season by pouring water into the pit and confirming the float triggers the pump. Never discharge a sump pump into the sanitary sewer. It’s exactly the system you’re trying to keep from overloading.
Outside, keep roof runoff away from the foundation and the sanitary system. A common rule of thumb is roughly six inches of fall over the first ten feet away from the house, so the ground sheds water rather than pooling over the lateral route during a storm.
The monsoon season officially runs June 15 through September 30, so spring is the time to deal with a lateral that’s already given you a warning. Camera first, jetting if the pipe needs cleaning, then a valve if reverse flow from the main is the actual problem.
Talk To Evolution
We work across Gilbert, Chandler, Mesa and the wider Valley on both sides of this: same-day help when a sewer is backing up, and planned camera inspections, jetting and backwater-valve work before the next monsoon.
Not sure whether it’s your lateral or the Town main? Whole street backing up means call the Town. Only your house means call us. We’ll inspect your side, show you the camera footage, and give you a straight answer about what’s actually worth fixing. Ask when you book whether the inspection charge can be credited toward any repair you approve.
Call (480) 662-6555, or reach the team through our contact page, to schedule an inspection or get help with an active backup.
