Unblock Drain Yourself New Malden | When to Stop and Call

Most drainage engineers won't say this, but a fair chunk of the calls we get in New Malden didn't need us. Not because we're complaining. Just because it's true, and you deserve to know it before you spend money.

Some drain problems are genuinely a five-minute fix with a plunger and a kettle. Others look the same from the outside but are quietly turning into something expensive underground. Knowing which is which saves you either a wasted call-out or a far bigger bill down the line.

The jobs you can almost certainly handle yourself

A slow kitchen sink. Probably a grease build-up just inside the trap. Pour a decent amount of boiling water down slowly, wait, repeat. If that does nothing, a half-cup of bicarbonate of soda followed by a half-cup of white vinegar and then boiling water shifts a lot of soft blockages. If the sink is in a ground-floor kitchen in Coombe or Motspur Park with older pipework, give it two or three attempts before assuming it's anything structural.

A sluggish bathroom basin. Nine times out of ten it's a hairball sitting right in the pop-up plug mechanism or just below it. Pull the plug assembly out (they usually unscrew or pull up with a quarter-turn), fish out whatever's down there with a bent wire coat hanger or a drain hair tool (about £3 from any hardware shop on Burlington Road), and run the tap. Job done.

A single blocked shower tray. Same culprit: hair and soap compacted around the drain cover. Remove the cover, clear the debris, run the shower. Wear gloves. It's grim but it's not complicated.

A smelly drain with no blockage. If water's draining fine but there's an odour, the U-bend has probably dried out (more common in guest bathrooms or utility rooms that don't get used much). Run the tap for thirty seconds. The water seal in the trap will reform and the smell will go. If it persists after that, it's worth a CCTV drain survey to rule out a cracked or displaced pipe, because that smell can also mean sewer gas.

Where most homeowners go wrong

The mistake isn't attempting DIY. The mistake is persisting with it past the point where it's making things worse.

Chemical drain cleaners are the big one. In Malden Manor and Green Lane we see a lot of older clay and cast-iron pipework. Some of the caustic lye-based products, poured repeatedly into a drain that isn't actually blocked by organic matter, will degrade mortar joints and attack older pipe materials. You spend £8 on a bottle, it does nothing because the blockage is a tree root forty feet down, and six months later you've got a worse problem. Use them once, sparingly, on a fresh organic blockage. Don't make them your go-to.

Another common one: plunging a toilet when there's a full blockage already sitting in the stack. You're not clearing it, you're compacting it tighter and potentially pushing it somewhere more awkward. If the toilet isn't shifting anything after ten or fifteen firm plunges, stop.

And the drain rods from the hire shop. Brilliant tool, genuinely useful, but only if you know which way to turn them (always clockwise, so the joints don't unscrew in the pipe and leave you with a rod stuck underground). In West Barnes and Coombe Vale we've recovered hire rods from drains more than once.

Signs you should stop and call

A few things that mean the DIY window has closed:

• More than one fixture draining slowly at the same time. A slow basin and a gurgling toilet together point to a shared drain issue, not individual blockages.
• Water backing up through a ground-floor drain or gulley when you run a tap elsewhere. That's a main drain blockage and it needs high-pressure water jetting, not a plunger.
• Any sign of damp or subsidence near where your drain runs. In Norbiton and Berrylands where a lot of properties were built in the 1930s and 40s, drain runs can be close to foundations. A leaking joint isn't just a drainage problem.
• The same drain blocking repeatedly, even after you've cleared it. That's a symptom of something structural: a collapsed section, a root intrusion, a bellied pipe. A CCTV drain survey will show it clearly and costs a fraction of what repeated emergency call-outs add up to.
• Sewage smell from multiple outlets, or from outside. That's a sewer defect until proven otherwise.

The honest caveat

Some of what I've described above is genuinely borderline. An external gulley that's blocked with leaves and silt in a Raynes Park back garden? Absolutely clear it yourself, that's a ten-minute job with a gloved hand and a hose. But the same gulley that clears fine and then fills back up two days later? That's telling you something. Don't ignore it because the fix looked easy the first time.

CCTV surveys exist precisely for the situations where you can't tell from the surface what's happening. They're not an upsell, they're a diagnostic tool. In a lot of cases they confirm the drains are fine and you get peace of mind. In others they catch a developing problem early, before it becomes a collapse or a flooded floor.

A few quick reference rules

• Single fixture, slow drain, no other symptoms: DIY first, always.
• Multiple fixtures affected: call before you try anything.
• Smell but no blockage: run the taps, then wait 24 hours before doing anything else.
• Recurring blockage: don't just keep clearing it, find out why it keeps blocking.
• Any groundwater, subsidence or damp near a drain run: don't touch it, get it surveyed.

None of this is about selling you a job you don't need. It's about not spending a Saturday wrestling with something that needs specialist kit, or ignoring something small that's quietly becoming expensive.

If you've worked through the DIY checks and you're still not sure, Drainsco covers New Malden and the KT3 postcodes with engineers available around the clock. There's no call-out fee, and you'll get a clear price before anyone starts work. Sometimes it really is a five-minute visit to confirm everything's fine. That's worth knowing too.