Septic tank emptying and maintenance

Your septic tank is either due an empty, already overdue, or you have no idea which. This page covers what emptying and maintaining a tank involves. It also shows how to tell when yours needs doing. It also covers what the law expects of you, and how we fix the faults we find.

Septic tank emptying removes the settled sludge and floating crust from the tank by tanker. That lets it carry on separating solids from liquid. Drainage Emergency empties, inspects and maintains septic tanks across Derbyshire and Nottinghamshire, including the outlet and soakaway. We work 24 hours a day from Mansfield Road, Derby. Call 01332 215521 for a routine empty, an inspection, or a tank that is backing up now.

What septic tank emptying involves

A septic tank is not a store for everything you flush. It is a settlement chamber. Heavy solids sink to the bottom as sludge.

Fats and paper float as a crust. Only the liquid in between leaves, through the outlet pipe to the soakaway. A soakaway is the buried run of perforated pipe or stone-filled trench that lets that liquid drain into the ground.

Emptying, which the Environment Agency calls desludging, takes the sludge and crust out. The liquid layer goes with them, because you cannot lift one without the other. Over the following days the tank refills with waste water and starts separating again.

The point of the visit is the sludge, not the water.

The waste goes to a licensed disposal site. You are entitled to ask anyone who turns up with a tanker whether they are a registered waste carrier.

Emptying does not clean the soakaway. Sludge that has been carried through into the outlet pipe is a separate job. It is where a drainage engineer earns their place over a tanker driver.

How often a septic tank needs emptying

There is no single interval that is right for every tank. How often yours needs emptying depends on several things. It depends on the size of the tank and how many people live in the house. It also depends on how much water they use, and on whether wipes, fat or heavy chemicals go down the drain.

The reliable method is to dip the tank and measure how fast the sludge is building. Then the interval is set from that, rather than from a rule of thumb.

The signs are hard to miss once you know them. Toilets flush slowly or gurgle. There is a sewage smell near the lid or over the soakaway. The ground over the soakaway stays wet, or the grass grows greener in a stripe. Waste backs up into the lowest gully (the grated drain outside the house) or the downstairs toilet.

Any one of those means the tank is past due or the soakaway is struggling. If you are seeing them now, call 01332 215521. We will dip the tank and tell you which it is.

Where septic tanks are in Derbyshire

Most of Derby is on the Severn Trent public sewer, so septic tanks start where the mains drainage stops. That also changes who is responsible. Off mains, there is no Severn Trent sewer to hand over to. Every metre of pipe from the house to the soakaway is the owner’s.

North of the office, up the Derwent valley, the mill towns of Belper and Duffield (DE56) sit twenty minutes away. Stone-built terraces and older village properties are the stock there. There is a higher share of septic tanks once you leave the main road.

North-west of Allestree, the lanes towards Kedleston Hall and Quarndon are largely off mains drainage.

South-east, around Elvaston Castle Country Park, are the villages of Elvaston, Thulston and Borrowash. There, septic tanks and soakaways start to replace mains drainage. Older village properties there have long private runs. On the lower ground near the Derwent, the soakaways struggle in a wet winter.

Septic tank inspection and maintenance

A maintenance visit checks the parts of the system that an emptying visit alone never looks at. We lift the lids and check the condition of the tank walls, the baffles and the dip pipes. The baffles are the internal walls that stop the crust escaping with the liquid. The dip pipes are the T-shaped fittings that draw liquid from below the crust.

We also check the depth of sludge and crust against the working depth of the tank. We check the outlet is flowing freely and that the liquid level sits below it. A level standing above the outlet is the first sign the soakaway is backing up.

Where the outlet or soakaway is in doubt, we run a camera down it. A closed-circuit television (CCTV) survey of the outlet pipe shows its condition. It reveals whether the pipe is cracked, root-damaged, silted or blocked with carried-over sludge. It also tells you whether the fix is a jetting job or a failing soakaway. Our CCTV drain survey page explains what the footage looks like and what the report covers.

Maintenance also covers the long run of private drain from the house to the tank. On a farmhouse outside Duffield, that run can be considerable. A blockage or an open joint on that run shows up as a slow toilet. That happens long before anyone thinks about the tank. High-pressure water jetting and desilting that run is part of the job.

You get a written note of what was found. You also get a recommendation for when the next empty is due. That is based on the sludge depth we measured rather than a fixed calendar.

Septic tank repair

The faults we find are mostly in the pipework and the soakaway, not the tank itself. Cracked or displaced outlet pipes, a collapsed inlet baffle and a blocked dip pipe are common faults. So are tree roots in the run to the soakaway, and a soakaway silted up after years of carried-over sludge. All of these are drainage repairs, and we do them.

Outlet and inlet pipework is repaired the same way as any private drain. Where the pipe is shallow and accessible, that means excavation and replacement. Where digging would mean lifting a drive or a patio, it means a no-dig patch or liner instead. That is cured in place inside the existing pipe. Our drain repair page covers lining and patching in detail.

Tank structure is a different matter. A brick or concrete tank might be cracked below the water line, or letting groundwater in. That usually means it is at the end of its life. We will say so plainly rather than sell you a repair that will not hold. Replacing it with a modern treatment plant is a specialist installation.

Then there is the soakaway. We can jet and clear an outlet blocked with sludge. We can also survey the soakaway to confirm whether it has failed.

Installing a new soakaway or drainage field is not a service we offer. Where the survey shows that is what is needed, you get the footage and the report. Take that to a specialist installer.

The rules for septic tanks in England

If you own a septic tank in England, you have to meet the Environment Agency’s general binding rules. If you meet them all, you do not need a permit. We checked the current rules on gov.uk when writing this page. In plain terms they say:

• It must discharge to the ground through a drainage field, also called a soakaway, and never to a watercourse, ditch, stream or river, by connecting to the public sewer, replacing the tank with a small sewage treatment plant, or installing a drainage field
• The sludge must be removed before it goes beyond the tank’s maximum capacity, and the company removing it must be a registered waste carrier
• The system must be operated and maintained in line with the manufacturer’s specification, and repaired or replaced if it is not in good working order
• If you sell the property, you must tell the buyer in writing about the system, where it is and how it has been maintained

Two related things get confused with septic tanks.

A cesspit, or cesspool, is a sealed tank with no outlet at all. Nothing leaves it, so it fills with everything and has to be emptied far more often. We do not empty cesspits; if that is what you have, you need a tanker firm. We can confirm which you have on a visit, because the two are often mislabelled on older Derbyshire properties.

A soakaway is not a device you buy. It is the drainage field the tank relies on. As above, we clear and survey existing ones but do not install new ones.

What happens when you call

When you ring 01332 215521, any hour on any day of the year, tell us where the property is. Tell us what the problem is. Also tell us whether you know where the tank and its lids are. If you do not know, finding them is part of the visit.

For a maintenance or inspection visit we agree a time. The engineer who attends is the one who would run the camera. They would also jet the outlet if the lids reveal a problem.

That way you are not waiting on a second trade. For a backup into the house, we treat it as an emergency in the same way as a blocked sewer. Our emergency drain unblocking page explains how that works.

You get a quote before work starts, with no hidden fees. For jobs under two thousand pounds, you pay on completion. Every engineer is fully qualified, and the business carries £5 million of public liability insurance.

Drainage Emergency covers Derby, Derbyshire and Nottinghamshire from 33a, Parker House, Mansfield Rd., Derby DE21 4SZ. Customers regularly report us arriving within the hour for emergencies. The engineers they name in reviews, Chris, Dave and Phil, are the people who will turn up.

Call 01332 215521 and we will come out, lift the lids and dip the tank. By the time we leave, you will know how full it is. You will also know whether the outlet and soakaway are sound, and when it next needs emptying.