Sewage emergencies are stressful, unpleasant and potentially hazardous.
If wastewater is backing up, sewage is overflowing or alarms are sounding, fast action can reduce damage and contamination risk.
This guide explains what to do first and when to call a professional.
Quick Answer
Stop using water if sewage is backing up, keep people away from contaminated areas, do not attempt unsafe repairs, and contact a professional quickly.
Alarms, overflow, rising levels and system shutdowns should be treated seriously.
Sewage Backing Up Into the Property
This is urgent. Stop using toilets, sinks, baths, showers and appliances that discharge water.
Keep children and pets away from contaminated areas.
Pooling Wastewater Outside
Pooling wastewater near a tank, chamber or drainage field can indicate system failure, outlet blockage or overload.
Avoid contact and arrange inspection as soon as possible.
High-Level Alarms
A high-level alarm may indicate pump failure, blockage or rising liquid levels.
Do not ignore the alarm or simply reset it without checking the cause.
Complete System Shutdown
A failed treatment plant or control system can quickly lead to overflow or poor treatment.
Electrical faults should be checked by a competent engineer.
What Not to Do
Do not keep using water if the system is backing up. Do not enter chambers or attempt electrical repairs.
Do not use chemicals as a substitute for diagnosis if the system has failed.
Common Causes
Emergency issues can be caused by blockages, pump failure, power loss, sludge build-up, outlet restriction, overload or drainage field failure.
See common sewage system problems for related warning signs.
After the Emergency
Once the immediate issue is controlled, the system should be assessed for root cause and prevention.
Regular servicing can reduce risk; see the maintenance guide.
Get Emergency Support
Alton Facility Services provides sewage system diagnostics, repairs and support across Hampshire, Surrey and nearby areas.
Need urgent help? Contact our team or call 01420 561661.
What not to do during a sewage emergency
Do not keep flushing toilets or running appliances to “test” whether the problem has cleared. If the system is already surcharged, extra water can make the overflow worse and may push contamination into the property or garden.
Do not enter tanks, chambers or confined spaces. Sewage systems can contain harmful gases, unstable covers, electrical hazards and contaminated water. Keep covers secure unless a competent contractor is attending.
Information to have ready when you call
Useful information includes the property location, whether the issue is inside or outside, whether alarms are sounding, whether there is an obvious manhole or tank, whether the system is septic tank, treatment plant or pump station, and whether sewage is escaping.
Photos of the affected chamber, alarm panel, treatment plant lid or flooded area can help the office understand whether you need tanker attendance, pump engineer support, drainage work or treatment plant maintenance.
How AFS would investigate this on site
For off-mains drainage issues, we would normally start by checking the tank or treatment plant, inlet and outlet pipework, alarms, pumps, blowers, sludge levels, drainage field condition and any signs of surcharge or pollution.
If the issue looks compliance-related, we would also consider whether the existing arrangement needs septic tank conversion, a new sewage treatment plant installation, or planned treatment plant maintenance rather than another temporary repair.
When this becomes urgent
You should treat the problem as urgent if sewage is backing up into the property, wastewater is escaping outside, alarms are sounding repeatedly, electrical equipment is wet, or the system is close to overflowing.
In those situations, stop unnecessary water use, keep people away from contaminated areas and arrange professional attendance. Where the system needs emptying before repair, sewage tanker services may be required to control the level safely.
Useful related AFS services
The most relevant AFS services for this topic are sewage treatment plant installation, treatment plant maintenance, septic tank conversion and sewage tanker services. These pages explain the practical options in more detail.
Need practical help with this?
For sewage treatment plants, septic tanks, private drainage systems and tanker support across Hampshire, Surrey and nearby areas, AFS can inspect the system and recommend the practical next step. You can call 01420 561661 or send details through the contact form.
Call AFS on 01420 561661 or send the details through for practical advice.
Contact AFSFrequently asked questions
What should I do if sewage backs up?
Stop using water, keep people away from contaminated areas and contact a professional immediately.
Is a treatment plant alarm urgent?
Yes. Alarms can indicate rising levels, pump failure or control faults and should be investigated quickly.
Can I fix a sewage emergency myself?
Only basic safe checks are sensible. Avoid chambers, contamination and electrical components.
What causes sewage overflow?
Common causes include blockages, pump failure, sludge build-up, overload and failed outlets.
How can I prevent future emergencies?
Regular servicing, emptying and prompt repairs are the best prevention.
Can AFS inspect a private sewage system before quoting?
Yes. For sewage treatment plants, septic tanks, pump chambers and private drainage systems, AFS can inspect the site, identify the likely cause and advise whether servicing, repair, tanker attendance, conversion or replacement is appropriate.