Sewer cleaning and sewer unblocking

Unblocking or sewer cleaning: what's the difference?

Unblocking and sewer cleaning sound similar, but they're two different jobs. To unblock a drain, the engineer opens up a passage so the water can run away again. Sewer cleaning goes further: it cleans the entire inside of the pipe, removing not just the blockage but also the deposits on the pipe wall where the next one is already forming.

The difference shows most in pipes that have been in use for years. Grease and silt can narrow a 110 or 125 millimetre underground drain until only a thin channel is left. A drain snake will poke a hole through it, but within a few months the pipe is blocked again. High-pressure sewer cleaning strips that layer from the whole circumference, restoring the pipe to its original bore.

What builds up in a sewer

Kitchen grease

Hot frying fat and gravy seem perfectly liquid as they go down the sink. In the cool underground drain, though, they solidify and cling to the pipe wall, and everything that passes sticks to them in turn. After a few years there's a hard, yellow crust inside the pipe, often thickest in the first few metres after the kitchen connection. If your problems started with a slow kitchen drain, see our page on kitchen sink unblocking as well.

Root intrusion in older pipes

Many older homes still have clay or concrete pipes with socket joints. Over time, small gaps open up at those joints, and tree roots never fail to find them: inside a sewer pipe it's damp and full of nutrients. A hair-thin root works its way in and grows into a dense mat that catches toilet paper and grease. We mostly see root intrusion at properties with trees, hedges or large shrubs above or beside the pipe.

Subsidence and sand

Many homes are built on clay or peat, and that ground slowly settles. As a result, a pipe that was once neatly laid to a fall can sag at one point. Water always stands in a dip like that, and sand and silt settle in it. A shifted joint also forms a ridge that dirt gets caught behind. Sand often gets in through downpipes connected to the sewer, or through a crack in the pipe.

What doesn't belong in the sewer

Wet wipes, kitchen roll, tampons, cat litter and cotton buds don't break down the way toilet paper does. They snag on a ridge or a root and form a blockage that keeps growing. Building waste, such as cement residue after a renovation, can also narrow a pipe without anyone noticing.

Indoor drains, outdoor drains and the property boundary

A home's drainage has two main parts. The indoor drainage runs in and under the house: the waste pipes, the soil stacks and the underground drain beneath the floor. From there the pipe runs outside, under the garden or pavement, to the municipal sewer in the street.

As a general rule, anything on your own property is your responsibility as the owner, while the part under public land usually falls to the municipality. Exactly where the line is drawn varies between municipalities; often it's the property boundary or an inspection chamber just beyond it. If you rent, the landlord normally deals with the sewer, and in a block of flats it's often the VvE (owners' association).

When there's a blockage, that distinction matters. If the blockage is on the street side, it may be a matter for the municipality. A camera inspection of the sewer shows how far from the inspection chamber the problem is, so you know whose door to knock on.

Check the inspection chamber yourself first

A dirty sewer usually gives you some warning: several drains slow down at once, the toilet gurgles when the shower is running, and there's a sewer smell around the inspection chamber in the garden. If the sewer is completely blocked, nothing drains away anywhere and the water comes up at the lowest point in the house. A sewer blockage like that first has to be cleared, and then the pipe needs a thorough clean. To find out where the problem is, start by looking in the chamber.

Many homes have an inspection chamber with a round or square cover next to the outside wall or at the edge of the garden. Wearing work gloves, you can safely lift the cover and see what's going on:

• The chamber is full of water. The blockage is further along, towards the street.
• The chamber is empty, but nothing drains away indoors. The blockage is between the house and the chamber.
• The water is flowing, but slowly and with a lot of floating debris. The pipe has narrowed and is due for a clean.

Don't climb into the chamber, don't put your hands in the sewage, and keep children and pets well away. Put the cover back securely afterwards. And don't pour chemical drain unblocker into the chamber or the drains. In an underground drain it gets so diluted that it does very little, yet the corrosive liquid is still there in the water the engineer will have to work in. If sewage is coming up through a drain in the house, or the crawl space smells strongly of sewage, stop using water and call us.

Our approach: high-pressure sewer jetting with the right nozzle

Nozzle and hose

High-pressure sewer jetting means feeding a hose with a jetting nozzle into the pipe. The nozzle's holes spray backwards at an angle, so it pulls itself along the pipe and flushes the dirt back out. The engineer usually works from the inspection chamber, first towards the street and then back towards the house. If the pipe is completely blocked, sewer unblocking comes first: a rotating head or a drain snake opens up a passage, and the cleaning follows.

Cutting through roots and hard deposits

Water alone isn't always enough against roots and hardened grease. In that case, the engineer uses a root cutter or chain flail to knock roots and crusts off the pipe wall, then flushes everything away. Roots grow back as long as the opening in the pipe is there, so we'll also advise you on repairing the joint.

Checking the result

Afterwards, we run plenty of water through the pipe and check in the inspection chamber that it's flowing freely. If there was any doubt about the state of the pipe, a camera inspection follows. We then tell you what we found and what most likely caused it.

What sewer cleaning costs

Our prices start from €129, and the call-out charge comes on top of that. For work in the evening, at night, at the weekend or on a public holiday, we charge the out-of-hours rate.

Cleaning a long stretch of sewer, cutting out roots or combining the work with a camera inspection is priced individually, so for jobs like these just ask for a quote. You'll always get a price estimate over the phone first, and the engineer won't start until you've agreed.

Preventing backflow and keeping the pipe clean

With a combined sewer system, rainwater and waste water share the same pipe. In a cloudburst, the public sewer can fill up so much that water is forced back towards the lowest drains in your home, such as those in a cellar, a basement flat or a ground-floor shower. A non-return valve in that drain prevents this. To keep the pipe itself clean:

• pour fat and oil into a jar, put the lid on and throw it in the general waste;
• put wipes, kitchen roll and cat litter in the bin, never down the toilet;
• don't plant trees or large shrubs right above the sewer pipe;
• keep the leaf guard at the bottom of the downpipe clean, so sand and leaves don't wash into the sewer;
• have an old garden sewer near trees cleaned regularly, just as you would the pipes from a commercial kitchen.

If the downpipe also overflows in heavy rain, or water bubbles up at its base, the blockage is often in the rainwater drain itself. Our page on downpipe unblocking explains more.

Emergencies and service area

Sewage in your home can't wait until Monday. If it's coming up through a drain or the toilet, it's not just unpleasant but unhygienic too. Our sewer service is available day and night on 085 333 4698, Sundays and public holidays included, and the engineer is usually with you within the hour.

We carry out sewer cleaning in Rotterdam, Den Bosch, Enschede and Apeldoorn, among other places, and we clean sewers elsewhere in the Netherlands too; the page on our service area covers a number of cities in more detail. The best approach depends on the address: the soil type, the age of the neighbourhood and the trees in the street all play a part.