Septic Emergency: What to Do When Your System Backs Up

A septic backup is one of those emergencies that demands immediate action. Here’s exactly what to do, in order, when things go wrong.

Step 1: Stop Using Water — Right Now

This is the most important thing you can do in the first five minutes.

Every time you flush a toilet, run the dishwasher, do a load of laundry, or take a shower, you’re adding volume to an already overwhelmed system. Water has to go somewhere. If the septic system can’t accept it, it comes back into the house through the lowest fixture — usually a basement floor drain, a first-floor toilet, or a bathtub.

Turn off the washing machine if it’s running. Tell everyone in the house to stop using water until further notice. A family of four producing normal morning water use can push 50-100 gallons into the system in an hour. That’s 50-100 gallons that has nowhere to go.

Minimum use only: If you need to flush a toilet, flush it once and wait. Don’t run anything else at the same time.

Step 2: Don’t Add Chemicals or “Septic Treatments”

In a panic, some homeowners reach for septic treatment products — enzyme treatments, bacterial additives, drain chemicals, or baking soda/vinegar combinations they’ve read about online.

Do not pour anything into your system during a backup event. Drain chemicals can damage tank components and kill the beneficial bacteria that make the system work. Enzyme treatments are at best useless during an acute failure. None of these products will clear a blocked outlet, unclog a distribution box, or relieve a flooded leach field.

The only thing that helps right now is getting a professional on-site.

Step 3: Call for Emergency Septic Service

In Franklin County, several contractors offer emergency septic service. When you call:

• Describe exactly what you’re seeing. “Sewage backing up into my basement floor drain” tells the tech something very different from “slow drains in the kitchen.”
• Tell them if sewage has already surfaced inside or outside. This affects both the urgency and the regulatory requirements.
• Give your address and access information. Is the tank accessible? Is the driveway plowed if it’s winter?

Franklin County contractors with known emergency service availability include:

• Harris Septic — serves Greenfield and surrounding towns
• River Valley Excavating — Franklin and Hampshire County
• Complete Septic — Franklin County
• Fletcher Sewer & Drain — Franklin County drain and jetting service

Emergency service typically costs more than a standard pump-out — expect $500-$900 or more depending on timing (nights and weekends carry a premium). That said, don’t delay calling to shop around. A backed-up system inside your home is a health hazard.

If Sewage Has Backed Up Inside the House

Raw sewage contains pathogens — bacteria, viruses, and parasites that can cause serious illness. If sewage has surfaced inside your home, treat the area as a biohazard:

• Don’t walk through sewage in bare feet or soft-soled shoes
• Wear rubber gloves and avoid touching your face
• Keep children and pets away from the affected area
• Don’t run fans that blow air from the sewage-affected area to the rest of the house
• Document the damage with photos before cleanup for insurance purposes

Professional sewage cleanup (after the septic issue is resolved) is worth the cost. Sewage contamination in walls, flooring, or subfloor requires proper remediation — it doesn’t just dry up and go away.

What the Service Tech Will Check First

When the contractor arrives, they’ll typically start by locating and opening the septic tank. Here’s why that matters:

If the tank is very full or overflowing: The primary problem is the tank — it may not have been pumped in too long, or there may be a blockage at the outlet. The pump-out provides immediate relief and resolves the backup.

If the tank is nearly empty: This is actually the more serious finding. An empty tank during an active backup means effluent can’t exit the tank — the outlet is blocked, or more likely, the leach field is saturated and backing up into the tank. The pump-out may provide temporary relief (a few hours to a few days), but it doesn’t fix the underlying problem.

If the tank level is normal: The problem may be in the building drain or lateral — a clogged pipe between the house and the tank. A drain jetting service may clear it.

The difference between these scenarios matters a lot for what happens next.

Spring Backups: The High Water Table Scenario

A significant percentage of septic “emergencies” in March and April in western Massachusetts are actually high water table events, not system failures.

Here’s what happens: Winter snowpack melts rapidly, often during warm rain events. The water table rises, sometimes dramatically — in low-lying areas near the Connecticut River, Millers River, or in towns like Montague, Deerfield, and areas near the Quabbin watershed, this can raise groundwater to within 12-18 inches of the surface.

Your leach field can only drain into unsaturated soil. When the surrounding soil is fully saturated, effluent has nowhere to go. The system backs up even though there’s nothing mechanically wrong with it.

Signs it’s the water table rather than system failure:

• Problem coincides with rapid snowmelt or heavy extended rain
• No problems in other seasons
• Backup clears up within days as soils drain
• Tank pumped recently and no other symptoms

What to do: Emergency pump-out provides temporary relief by creating holding capacity. Reduce water use until soils drain — this often takes 3-7 days after the precipitation event. Do not attempt to “fix” the system by adding chemicals or aerating the field.

If the same pattern repeats every spring, that’s a sign the system was installed in a location with inadequate separation from seasonal high water table. That’s a design issue that warrants discussion with a licensed engineer about long-term solutions.

After the Emergency Pump-Out

An emergency pump-out stops the immediate crisis. It does not fix the underlying cause.

After the technician leaves:

• Find out what they found. Ask what tank level they found, whether baffles were intact, and whether they saw anything concerning.
• Get a follow-up inspection. A Title 5 inspection or a septic system assessment from a licensed contractor will tell you the actual condition of the system.
• Address the cause. If this was a simple too-full-tank situation, commit to a regular pumping schedule. If there’s a more serious issue — failing leach field, cracked distribution box, deteriorated baffles — get estimates for repair before the next emergency.

DEP Reporting Requirements

If sewage has surfaced on your property and is in, or at risk of reaching, surface water (a stream, pond, wetland, or ditch that drains to a water body), Massachusetts DEP requires notification. Call DEP’s 24-hour emergency line at 1-888-304-1133. This is a legal requirement, not optional.

The Board of Health in your town may also need to be notified. When in doubt, call them.

Preventing the Next Emergency

Most septic emergencies are preventable:

• Pump every 3-5 years — more frequently for larger households
• Never flush wipes (even “flushable” ones), feminine products, medications, or excessive paper
• Spread laundry loads throughout the week rather than doing five loads on Saturday
• Keep trees away from the leach field — root intrusion destroys systems
• Know where your system is — so you don’t drive over it, plant trees near it, or cover lids with landscaping

The 413Septic.com contractor directory can help you find the right contractor for follow-up work after an emergency.