Water standing in an outside drain is unpleasant, but the important question is where the obstruction lies. A blocked gully next to the kitchen wall is different from a blockage in the underground pipe serving the toilet. And neither necessarily means the drain has collapsed.
Start by looking at what is happening, rather than trying to force more water through the system.
Is it the outside gully or the underground drain?
The small gully receiving water from a kitchen waste pipe or rainwater downpipe may collect leaves, grease and sediment. If only that gully overflows and the toilet and other fixtures empty normally, the restriction may be local to the gully or its outlet.
If an outside inspection chamber fills with dirty water, or flushing the toilet makes sewage rise at another opening, the obstruction may be further along the foul drainage system. Several affected appliances are a stronger clue than one slow sink.
Rainwater and foul sewage do not always share the same pipe. Older properties can have combined drainage, whereas other homes have separate rainwater and foul systems. Do not assume that every outside grate connects to the sewer carrying toilet waste.
What to do straight away
If wastewater is rising or sewage is visible, stop flushing toilets and avoid using sinks, showers, washing machines and dishwashers connected to the affected drain. Each use may add to the overflow. Keep children and animals clear, and do not touch contaminated water without suitable protection.
Do not lift a heavy or stuck manhole cover, lean over an open chamber or enter one. Sewers can contain dangerous gases and hazardous atmospheres. Never mix drain-cleaning chemicals, and tell the contractor if chemicals have already been used.
If sewage is reaching the house, move belongings away from the affected area only where you can do so safely. If the situation creates an electrical hazard, keep away from affected electrical equipment and seek appropriate professional assistance.
Who should clear a blocked outside drain?
In England and Wales, a drain serving only your property within its boundary is normally the responsibility of the owner or landlord. Public sewers, many shared sewers and lateral drains beyond the property boundary are generally the sewerage company's responsibility. The manhole's position alone does not prove who owns the pipe.
If neighbours have the same problem, or a chamber serving several properties is overflowing, contact your sewerage provider promptly. Ask them to check responsibility before commissioning private work. Different arrangements may apply in Scotland and Northern Ireland. Tenants should inform their landlord or managing agent as well.
For a useful explanation, see Ofwat's guidance on drains and sewers.
Why the blockage may have happened
Fat, oil, grease and wipes can accumulate in foul drains. Tree roots may enter through a defective joint. A poorly supported pipe may develop a displaced connection or a low point where solids settle. Sometimes the obstruction is much farther down the line than the overflowing gully.
A contractor might use rods or suitable jetting equipment to clear an accessible blockage. But there is little benefit in repeatedly clearing the same pipe if its condition has not been checked. If the blockage is recurring, ask whether a CCTV inspection would establish a cause.
What to tell the drainage contractor
Explain exactly where the water appears and what causes it to rise. Is the kitchen sink slow? Does the toilet flush normally? Does the problem happen only after heavy rain? Has it happened before, and how recently was the drain cleared?
Before agreeing to work, ask for the call-out cost, what is included in a basic clearance, and how additional camera work or repairs will be authorised. Ask the contractor to demonstrate that the drain is flowing properly after clearance, rather than simply saying the blockage has gone.
A claimed collapse or major repair should be supported by evidence, preferably with the relevant camera footage and the location of the fault.
If the outside drain keeps blocking
A one-off obstruction may be straightforward. Two or three blockages in the same location, particularly shortly after jetting, tell a different story. The cause may be a defective joint, roots, a sagging pipe or recurring material entering the drain. Read our guide to drains that keep blocking before agreeing to repeated clearances.
If sewage is overflowing now, checking the likely cause can wait until the immediate flow has been made safe. Once the drain is clear, an investigation may save further disruption and expense.
Need a local drainage contractor?
If the blockage appears to be in a privately maintained drain, you can request quotations from drainage specialists through MyJobQuote. Explain whether sewage is overflowing, how long the problem has been present and whether the drain has already been cleared.