Gully Emptying: What It Costs and How Often Your Site Needs It

Gully emptying is the job of removing the silt, leaves, grit and litter that collect in the pots of surface water gullies, so rainwater can reach the drain instead of pooling on the surface. What it costs depends on how many gullies there are, how full they are, how easy they are to reach and how the waste has to be disposed of. For most commercial sites the cheapest way to buy it is as a scheduled line in a planned maintenance contract, not as a reactive call-out after the car park has flooded.

What is gully emptying, and why does it need doing?

A gully is the grated inlet that takes rainwater off a yard, car park, driveway or loading bay. Below the grate is a pot that traps solids so they do not wash into the pipe, and that pot fills up over time.

Once the pot is full, silt starts to pass into the drain beyond it, where it settles and narrows the pipe. Water then backs up at the grate and the surface floods in heavy rain. On commercial sites that means standing water in car parks, ice in winter and, on loading bays below ground level, water heading for the building. Emptying the pots on a schedule is far cheaper than jetting silt out of the pipes after it has got into them.

What does a gully emptying visit involve?

On most commercial sites the pots are emptied by suction from a vacuum tanker, the gully is washed through, and the waste is taken away for licensed disposal. A good visit also checks that each gully drains freely afterwards.

The engineer lifts each grate, sucks out the pot, and flushes the outlet so water runs through to the drain. Where silt has already passed into the pipe, the connection may need high-pressure jetting to clear it, which is a separate job and should be priced as one. A few domestic gullies can be emptied by hand, but a car park with dozens of gullies needs a tanker, and that equipment is part of what you are paying for. The waste is controlled waste, so whoever removes it must be a registered waste carrier and should give you a waste transfer note. Keep those notes: they are your evidence that the waste went somewhere lawful.

What sets the price of gully emptying?

Five things move the price: the number of gullies, how full they are, access for the tanker, the time of day the work is done, and the volume and type of waste to be disposed of.

• Number of gullies. Most of the cost of a visit is getting the tanker and crew to site. Each extra gully adds less than the first, so sites with many gullies pay less per gully.
• How full they are. A pot emptied on schedule is quick. A pot left for years, packed solid and draining into a silted pipe, takes longer and produces more waste.
• Access. A tanker needs to park close enough for its hose to reach. Gullies at the back of a busy car park, under parked cars or in a basement loading bay add time. Some sites have to be done early or out of hours when the car park is empty, and that is usually charged at a different rate.
• Disposal. Disposal is charged by volume, so fuller gullies cost more to dispose of as well as to empty. Waste contaminated with fuel or oil costs more again.
• Extras. Jetting the outlet pipes, replacing broken grates or clearing a blocked connection are separate items. A fair quote lists them separately rather than folding them into one figure.

How is gully emptying different from interceptor emptying?

A gully traps silt. A petrol or oil interceptor separates fuel and oil from surface water before it reaches the drain. They are emptied with similar equipment but the waste is treated differently, and that changes the price.

Interceptors are common at car parks, forecourts, vehicle workshops and wash bays. Their contents are usually classed as hazardous waste, which carries stricter paperwork and higher disposal costs than ordinary gully silt. If your site has both, make sure a quote names each one separately, so you can see what the interceptor adds and check that its waste is being handled under the right paperwork.

How often do gullies need emptying?

For most sites, at least once a year, and more often where leaves, grit or heavy traffic fill the pots faster. The right interval is the one that stops the pots filling to the point where silt reaches the pipe.

Sites under trees usually need a visit after leaf fall in late autumn. Busy car parks, service yards and sites near building work fill with grit much faster. A useful approach is to empty everything once, note how full each pot was, and set the next interval from that: pots found nearly empty can be left longer, pots found packed need more frequent visits. The same logic applies to the rest of the site's drains, which our guide to how often commercial drains should be cleaned covers in more detail.

Who is responsible for emptying a gully?

The owner of the land the gully drains is usually responsible for it. Gullies on your car park, yard or private road are yours; gullies in the public road or pavement belong to the highway authority.

If the flooding is from a road gully outside your premises, report it to the council or, on red routes, to Transport for London, rather than paying to empty it. On a shared site, such as an industrial estate or a block with a communal car park, the lease or management agreement usually says whether the landlord, managing agent or individual tenants pay. Check it before instructing work.

How do you compare gully emptying quotes?

Compare the price per visit for the whole site and what it includes, not just a price per gully. Ask each contractor the same questions so the quotes can be compared line for line.

• How many gullies and interceptors does the price cover, and are they listed?
• Is disposal included, and is a waste transfer note provided?
• Does the price include flushing the outlets and checking each gully drains?
• What does jetting a silted connection cost if one is found?
• Is the work done in normal hours, and what is the rate if it has to be out of hours?

For sites that want gullies emptied alongside planned jetting and camera checks, we price each item separately in our commercial drainage maintenance contracts, so you can see what the gullies cost on their own and adjust the frequency without renegotiating the whole contract.