Using a drain snake on old pipes? Here’s what you need to know
Old pipework has its own character: it was often built robustly, but after decades of use has become fragile due to corrosion, hairline cracks and subsidence. Using a drain snake in such a system seems logical you want to restore flow without breaking open walls but the wrong approach can cause more damage than the blockage itself. In this guide, Riool Centrale Nederland explains when a snake is sensible, how to recognize material- and age-related risks, and which techniques do work safely with cast iron, stoneware (gres), zinc or lead. This way you avoid a quick fix turning into leakage, recurring problems or a necessary renovation.
Why old pipes react differently
Pipes from the pre-PVC era (think cast iron, stoneware/ceramic, asbestos cement, zinc and sometimes lead) don’t just age on the inside. Corrosion, limescale, grease and soap buildup, and micro-settling make the walls rough and the joints vulnerable. With stoneware, joints are often sealed with mastic, tar or cement; with cast iron, bell-and-spigot connections were traditionally filled and may have loosened after decades. An aggressively forced drain snake can pry open such a joint or turn a hairline crack into a fracture. Sharp bends (“90-degree elbows”) and saddle connections to the main stack are also risky: push through with too much torque and too little control, and the snake head may get stuck or cut into the edge.
When a snake does make sense
Not every blockage is the same. Build-up of soap and grease (kitchen/bathroom), hair and toothpaste (sink), or a wad of paper just behind the toilet usually respond well to controlled use of a drain snake. The key is to break up the resistance locally while maintaining constant control of direction, torque and retrieval. If the issue lies deeper in the system (under the floor or in the main stack), or if you hear recurring gurgling in other drains, measuring and inspecting first (camera/flow test) is wiser. Root intrusion (in outdoor stoneware) or sagging sections will not be solved permanently with a snake alone; those require other techniques.
Head choice, diameter and drive
A snake is not just a piece of wire. With old pipes, choose a soft to medium drain snake with enough flexibility and a head that fits the job: a corkscrew/claw for paper and fibers, a pear-shaped head or small cutter for grease and soapstone. Bigger is not better: too-wide heads bang against joints and wear out bends. Electrically powered machines give constant speed and torque, which is convenient, but with fragile materials you actually want variable power and a slow start. A manual snake or machine with infinitely adjustable rotation prevents “overshoot” in old joints. Important: always feed the snake in pulses (short in, short out) instead of pushing through; this way you don’t “drill” into a weak spot and you immediately feel whether you’re going through a bend or through debris.
When not to use a snake
There are scenarios where you should leave the snake in the box. Lead drains in old bathrooms may be dented or thinned; a snake can quickly tear them. Stoneware with known cracks or sagging can be “pried open” by a rigid head. Asbestos cement (old outdoor runs) requires specialized handling; aggressive mechanical cleaning is not an option there. Also after recent construction damage (drilling into walls, tile renovations), there’s a real chance a screw has punctured the pipe. A snake that catches on such a spot can get stuck permanently. In short: if the source of the problem is unclear, start with a camera; only then decide if a snake is the right tool.
Alternatives that spare old pipes
High-pressure cleaning with a rotating nozzle is effective, provided pressure and flow are matched to material and diameter. In old houses, we work with regulated pressure and backflow protection so joints don’t blow apart. Micro-cutters (with plastic guides) remove hard limescale or soapstone with minimal stress on the wall: ideal for cast iron that has built up “scale.” Sometimes a combination is needed: first light cutting, then a short flushing pulse. If the installation remains structurally unstable (sagging, multiple leaks), we discuss relining or partial replacement. The principle remains: as little invasive as possible, as durable as possible.
Prevention: Small habits, big effect
A lot of trouble comes from small habits: grease in the sink, coffee grounds, wipes, or a drain structurally connected too low and thus siphoning. With simple measures a fine-mesh strainer, a minute of hot water weekly through the kitchen drain, correct trap height, and a hair catcher in the bathroom you greatly reduce the risk of new clogs. In old houses it pays to have two things adjusted: replace sharp T-fittings with angled inlets (less buildup) and install an extra clean-out on the tricky run. Then future use of a drain snake will be short, controlled and without unnecessary risks.
In conclusion: Drain snake
With old pipes, the temptation is strong to grab the snake right away. Sometimes that’s exactly the right choice short, controlled and effective. But without insight into material, joints and ventilation, any drain snake is a roll of the dice. By first inspecting and measuring, choosing the right head and access point, and dosing torque and speed, you can turn a fragile system back into a reliable one. Riool Centrale Nederland is happy to help you with this, with expertise that you notice in your flow, not in your tiles.
Read more here:
https://rioolcentralenederland.nl/ontstoppingsveer/
