If your toilet keeps getting blocked, the problem is almost never with the bowl itself: it’s in the trap, the downpipe, the drain chamber or the sewerage system further down the line. An occasional blockage can be cleared with a plunger; a blockage that recurs every few weeks is a sign that something in the plumbing isn’t draining properly.
The most common causes of a toilet that keeps getting blocked are as follows:
- Wipes, sanitary towels, cotton buds and excess toilet paper flushed down the toilet.
- A cistern that dispenses little water or has a weak flow.
- Limescale and sediment build-up in the siphon and pipes.
- A downpipe or drainpipe with a gentle slope or poor ventilation.
- Blockages further down the line: blocked manholes, tree roots, breaks or sections that have subsided.
- In homes without mains drainage, a full septic tank.
In this article, we explain how to identify which of these causes is affecting your toilet, what you can do yourself to fix it, and when it’s best to call a drain-clearing company to ensure the problem doesn’t return.
Reasons why the toilet keeps getting blocked
A toilet that keeps getting blocked is almost always due to one of these seven causes. Identifying the cause is the first step towards avoiding having to unblock it every week.
1. Wet wipes and other non-biodegradable waste
This is the most common cause. Wipes, sanitary towels, tampons, cotton buds, dental floss or hair do not break down like toilet paper: they get caught in the trap or at the bends in the pipework and form a blockage that grows with every flush.
Even if the packaging says ‘biodegradable’, that doesn’t mean you can flush it down the toilet. In Spain, the UNE 149002 standard for toilet-flushable products specifies which products can be flushed and how they should be labelled; as a general rule, wipes belong in the bin.
2. Using too much toilet paper with every flush
Flushing a large amount of toilet paper all at once, especially if it is thick or multi-layered, can exceed the toilet’s flushing capacity. If you also use the half-flush button, the toilet paper gets stuck halfway down and builds up in the drainpipe.
3. Low-flush cistern
If the cistern does not fill completely, the float is incorrectly adjusted or the mechanism is leaking, the flush will not be powerful enough to carry away the waste. This also happens with some water-saving toilets that are not properly adjusted.
4. Limescale and sediment in the siphon and pipes
In areas with hard water, limescale builds up in the toilet’s siphon and inside the pipes. Over the years, the effective diameter of the pipes decreases, and what used to flow through without any problems begins to get blocked.
5. Poor drainage, slope or ventilation
If the pipe leading out of the toilet has too little slope, an insufficient diameter or the drainage system is not properly ventilated, the water drains slowly and solids build up. This is usually noticeable because the water rises in the bowl before draining away, or because gurgling noises can be heard in other drains. Basic Document HS 5 of the Technical Building Code sets out the requirements for diameters, gradients and ventilation of drainage systems.
6. Blockages further down the pipe: manholes, tree roots and breaks
When the blockage is outside the bathroom, unblocking the toilet only alleviates the symptom. The most common causes are manholes full of sediment, roots growing into the pipework, sunken sections or broken pipes. A clear sign: if flushing the toilet also causes the shower or washbasin to become blocked, the problem lies in the main drainage system.
7. Full septic tank
In holiday homes and country houses not connected to the mains drainage system, a toilet that is draining less and less effectively may indicate that the septic tank is full. Until it is emptied, the toilet will continue to become blocked even if it is unblocked. In this case, the solution is to have the septic tank emptied.
|
A sign that you notice |
Most likely cause |
What’s the problem? |
|---|---|---|
|
It’s just the toilet that’s blocked; the rest of the drains are fine |
Toilet wipes, excess toilet paper, the cistern or limescale |
Toilet bowl or siphon |
|
The water rises and falls slowly, with a gurgling sound |
Poor drainage or ventilation |
Bathroom drainpipe or branch pipe |
|
The toilet, shower and washbasin all get blocked at the same time |
Dirty manhole, roots or a break |
Domestic drainage system |
|
Bad smells and the toilet is flushing less and less effectively in a house with a septic tank |
Full septic tank |
Septic tank |
How to unblock a toilet: what you can do at home
If the blockage is in the bowl or the trap, you can try to clear it yourself by following these steps, starting with the least invasive and working your way up to the most invasive. If the problem returns after you’ve tried them, the cause lies further inside.
Step 1: Don’t flush the toilet again
If the water doesn’t drain away, each subsequent flush will raise the water level and may cause the toilet bowl to overflow. Turn off the cistern stop valve and remove the excess water with a bucket before you start.
Step 2: Use a suitable suction plunger
For toilets, a bellows-type or flanged plunger works best, as it seals the toilet bowl’s drain properly. Place it over the drain, with enough water to cover the rubber cup, and make firm pushing and pulling movements for a few seconds. Repeat several times before giving up.
Step 3: hot water and soap
A squirt of washing-up liquid followed by hot, but not boiling, water helps to loosen any bits of paper and grease. Boiling water can damage the porcelain or the seals, so avoid using it.
Step 4: spring or drain unblocking probe
If the plunger doesn’t work, a manual drain unblocker allows you to reach the trap and dislodge or remove the blockage. Insert it carefully so as not to scratch the porcelain, and turn it as you push it in.
What to avoid
- Chemical toilet unblockers. They can damage old seals and pipes, and if the blockage does not clear, the product remains in the bowl. Furthermore, their effects usually last only a few days.
- Impromptu objects such as coat hangers or sticks. They may scratch the pottery or push the stopper further in.
- Removing a toilet without any experience. If the toilet bowl needs to be removed, it’s best to leave it to a professional.
If you have followed these steps and the toilet becomes blocked again after a few days or weeks, the blockage is not in the bowl: it is in the downpipe, in a manhole or in the sewerage system, and household tools cannot reach that far.
When to call a drain-clearing company
It is advisable to call in a professional when the blockage keeps recurring, affects several drains at once, or cannot be cleared using a plunger and a drain snake. These are the clearest signs:
- The toilet gets blocked more than once a month, even when used correctly.
- When you flush the toilet, water rises in the shower, the bath or the washbasin.
- There are persistent unpleasant odours in the bathroom or near the drain covers.
- You can hear gurgling noises coming from other drains when the toilet is flushed.
- The house has a septic tank and the toilet is draining less and less effectively.
How we work at Limpiezas Domingo
At Limpiezas Domingo e Hijos, we carry out drain unblocking and pipe cleaning using a tanker lorry and high-pressure water for homes, businesses and housing estates. The service includes identifying the location of the blockage, high-pressure cleaning of the affected sections, suctioning out sludge and solids where necessary, checking the flow, and providing recommendations on use and maintenance.
If the blockage recurs or persists after cleaning, we recommend a CCTV pipe inspection. The CCTV camera allows us to view the inside of the pipe and detect roots, breaks or subsidence without having to open up the pipework – which is precisely what is usually behind a toilet that keeps getting blocked.
Depending on the findings, the solution may involve:
- Locate the blockage or break so that action can be taken only where necessary.
- Pipe milling to remove limescale, cement, roots and stubborn deposits.
- Pipe repairs without the need for building work, where the condition of the installation allows.
- Locating concealed manholes when it is not known how to access the network.
In the vast majority of cases, blockages are cleared without the need for engineering works; engineering works are only considered when there is structural damage to the pipework.
Service area
We have over 15 years’ experience and operate in the regions of La Marina and La Safor: Jávea, Dénia, Calpe, Teulada, Moraira, Benissa, Oliva, Gandía and nearby towns. We have dedicated web pages for drain unblocking services in the Marina Alta, Marina Baja and La Safor.
If your toilet becomes blocked at night or on a public holiday, we offer a 24-hour drain unblocking service and an emergency unblocking service to prioritise calls outside normal working hours. Call 672 450 224. If you’re in Dénia, we explain how it works in our article on 24-hour drain unblocking in Dénia using a vacuum truck.
How to prevent the toilet from getting blocked again
Most recurring blockages can be prevented by adopting simple habits and carrying out regular maintenance on the system.
- Only put toilet paper in the toilet. Put a bin in the bathroom for wet wipes, sanitary towels, cotton buds and hair.
- Flush the toilet fully when you put paper down the toilet. A half-flush is for liquids.
- Check the cistern. Make sure it fills to the correct level and that no water is leaking from the mechanism.
- Do not pour grease or food scraps down the drain. As they cool, they solidify and trap other waste.
- Carry out a preventative drain clean. If the blockage has recurred several times, a high-pressure clean will prevent it from happening again before it causes any problems.
- Empty your septic tank regularly if your home is not connected to the mains drainage system.
For owners’ associations, businesses, housing estates and property managers dealing with frequent issues, pipework maintenance contracts enable them to schedule preventative cleaning tailored to each individual installation.
Frequently asked questions about a blocked toilet
Why does my toilet get blocked if I only flush toilet paper?
If you only flush toilet paper down the toilet and it frequently becomes blocked, it is most likely that the cistern is not flushing enough water, that limescale has built up in the trap, or that the problem lies in the downpipe or a drainage chamber. If other drains are also blocked, the blockage is in the main drainage system.
How do I know if the blockage is in the toilet or in the pipe?
If it’s just the toilet that’s not working, the blockage is usually in the bowl or the trap. If, when you flush, water rises up through the shower or the washbasin, or you hear gurgling noises, the problem lies further down the pipe, in the downpipe, the main drain or a manhole.
Can ‘biodegradable’ wipes be flushed down the toilet?
As a general rule, no. Just because a product is biodegradable does not mean it will break down quickly enough in the pipework. Only products labelled as flushable in accordance with the UNE 149002 standard may be flushed down the toilet.
Are chemical drain unblockers suitable for the toilet?
They are not the best option. They can damage seals and pipes, and their effect usually lasts only a few days. If the blockage is a recurring problem, the most effective solution is to clean the pipe using high-pressure jetting and, if it happens again, to inspect it using a camera.
When is a camera inspection required?
When a blockage recurs, persists after clearing, or where there is a suspicion of breaks, tree roots or subsidence. The camera allows the exact source of the problem to be pinpointed and prevents the blockage from recurring.
Do you need to carry out building work to fix a toilet that keeps getting blocked?
In the vast majority of cases, no. High-pressure water jetting and suction clear blockages without the need for excavation, and some damage to pipes can also be repaired without digging trenches. Excavation is only considered when there is structural damage.
How much does it cost to unblock a toilet?
It depends on access, the length of the section, the extent of the blockage, and whether camera inspection or other work is required. At Limpiezas Domingo, we provide a quote that reflects the actual cost before carrying out the work.
Do you deal with blocked toilets outside normal working hours?
Yes. Limpiezas Domingo offers a 24-hour drain unblocking service and an emergency response service to prioritise out-of-hours calls in La Marina Alta and La Safor. For emergencies, call 672 450 224.
A blocked toilet always has a cause: find out what it is
A toilet that keeps getting blocked cannot be fixed by unblocking it every week; instead, you need to find out why it is getting blocked. If the toilet is being used correctly and a plunger is no longer enough, the problem is most likely in the downpipe, a manhole or the sewerage system.
At Limpiezas Domingo e Hijos, we identify the cause of the blockage, clear the pipes using a tanker lorry and high-pressure water and, if necessary, inspect them with a camera to ensure the problem does not recur. We operate in La Marina and La Safor from our base in Gata de Gorgos.
Call us on 672 450 224 or 966 447 070, or request a quote.