How to prevent drains from freezing this winter.
Let's be honest, most people don't think about their drains in winter until something goes wrong.
It starts with a slow sink.
Or a strange gurgling noise outside.
Or worse, an overflow that turns into a frozen, slippery hazard.
The truth is, frozen pipes because of blocked drains are incredibly common in cold snaps, mainly because there's not enough brackets on the small bore pipe coming from the kitchen sink. They can quickly escalate into damage, flooding, or system failure.
But it doesn't have to go that way.
The cold catches people out, every year.
At ASL Limited, homeowners and businesses across Surrey and the South have been helped for decades. Over the years, what works (and what doesn't) when it comes to keeping drainage systems safe in winter has been learned.
Why drains freeze, it's not just the cold.
Frozen drains usually happen when two things come together:
- Standing water in the pipe
- Freezing overnight temperatures
If your drain is partially blocked, even with a bit of fat, leaves, or debris, water sits still. When it gets cold enough, that water freezes in place, expanding and potentially cracking the pipe.
Even outside gully traps or soakaways can freeze if water builds up due to poor flow. That's where problems start.
The three worst culprits seen each winter.
Here's what gets called out for most often when the temperature drops:
1. Outdoor gully traps and kitchen waste pipes.
Fat and food waste solidify faster in the cold, especially in shallow runs near the surface. A little buildup becomes a full blockage overnight.
2. Surface water outlets.
If your garden, patio, or driveway doesn't drain well, the trapped surface water freezes, backs up the line, and causes damage upstream.
3. Poorly insulated pipes or joints.
This is especially common in older properties or DIY pipework where joins aren't sealed properly or insulation has deteriorated.
What you can do to stop it.
1. Jet or rod your drains before the cold sets in.
Clearing blockages before a freeze stops standing water from turning solid. This is one of the most cost-effective winter prevention steps.
2. Keep gully pots clear of leaves and debris.
Leaves collect in the gully and block water flow. Clear them out regularly, especially in late autumn and early winter.
3. Check that water is flowing freely.
Run water down outside gullies and kitchen waste lines. If it's slow to drain, something may already be partially blocked.
4. Add insulation to exposed pipes.
Some side temperatures are going to drop this year. In experience, sometimes you get caught out because the wind is blowing in a certain direction which didn't happen last year or the year before. Any pipes above ground or running along outside walls should be insulated, especially on north-facing walls that don't get sun.
5. Let warmth flow inside.
If your internal pipes run through colder areas (e.g. lofts, basements), keeping internal doors slightly open or using a gentle trickle of warm water during very cold nights can help prevent freezing.
What if it's too late?
If you suspect a frozen drain:
- Don't pour boiling water down the pipe. It can crack cold plastic.
- Call ASL Limited. All the gear is available to defrost, unblock, or reroute a problem drain quickly and safely.
Real example: frozen drain caused sewage backup in a holiday home.
A cottage near Farnham was called out to last January. The owner hadn't visited in weeks. Temperatures dropped, and the outside gully froze solid.
As people arrived for a weekend stay, they noticed the toilet was backing up.
The problem?
Fat had solidified in the kitchen waste pipe, blocking the gully. Water backed up through the whole system, eventually reaching the internal foul line.
One jetting and a short CCTV survey later, everything was sorted. But it was a stressful (and smelly) start to their weekend.
Winter drain care is a small job, until it's not.
Frozen drains seem like a small risk, until the day you can't flush the toilet or the kitchen floor floods.
At ASL Limited, helping you prevent the problem is preferred over being called out to fix a disaster. A quick pre-winter check, jetting, or cleanout could save you hundreds of pounds, and a whole lot of stress.
Think your drains might be at risk this winter?
❄️ Call ASL Limited now on 0800 181 684, or book a quick winter check-up.
The freeze will be avoided, fast.
We cover Surrey, Berkshire, Hampshire, West Sussex and South West London.
Related services.
To learn more about how ASL Limited can help protect your drains this winter:
