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Solvent weld waste pipe sizes: 25 mm against 32 mm

Updated: October 2026

The old basin waste is black, the stick on amazon.co.uk is black, and they are easy to treat as the same solvent weld waste pipe. Usual UK solvent-weld sizes are 32 mm, 40 mm, and 50 mm nominal. The only waste length here states 25 mm outside and 1 m. This page is that mismatch. The listings are on the [PVC pipe comparison](/hub/rods-and-pipes/pvc-pipe). A qualifying purchase can earn a commission at no extra cost to you. If you have not yet decided the job is waste, rather than a fan sleeve or a clear coil, start with the [PVC pipe buying guide](/hub/rods-and-pipes/pvc-pipe/sub/pvc-pipe-buying-guide).

The old basin waste is black, the stick on amazon.co.uk is black, and they are easy to treat as the same solvent weld waste pipe. Usual UK solvent-weld sizes are 32 mm, 40 mm, and 50 mm nominal.

Our top picks

eco-filtration eco-filtration 25 mm waste pipe

Best overall

eco-filtration eco-filtration 25 mm waste pipe
8.4/10about £10.20
View offer
Unifizz Unifizz 32 mm rigid pipe

Alternative

Unifizz Unifizz 32 mm rigid pipe
8.2/10about £8.89
View offer
TOP-VIGOR TOP-VIGOR 40 mm rigid pipe

Alternative

TOP-VIGOR TOP-VIGOR 40 mm rigid pipe
8.0/10about £8.89
View offer
On this page
  1. 1.What UK solvent-weld waste actually is
  2. 2.The 25 mm by 1 m listing
  3. 3.The short 32 mm and 40 mm sticks are not that system
  4. 4.What not to claim from the title

What UK solvent-weld waste actually is

Trade ranges sell solvent-weld waste in three nominal sizes. Brett Martin's own system is PVC-C to BS EN 1566-1 in 32 mm, 40 mm, and 50 mm. Approved Document H lists PVC-U sanitary pipework to BS EN 1329 and PVC-C waste to BS EN 1566. That is the materials route for a sanitary system. It is not printed on the listings here. The name is not the outside diameter. JDP's table puts nominal 32 mm at about 36 mm outside, nominal 40 mm at about 43 mm, and nominal 50 mm at about 56 mm. A socket at about 36 mm outside will not accept a pipe that states 25 mm outside. Kalsi, citing Approved Document H, gives unventilated branches of up to 1.7 m on 32 mm and up to 3.0 m on 40 mm. This set has no 3 m waste.

The 25 mm by 1 m listing

eco-filtration is black rigid PVC, 25 mm outside, wall about 2.5 mm, 1 m, at £10.20. Cement is not in the box. The star line is 4.2 from 17 reviews. Five UK texts call it the right size, and one says the joints fit without slipping. That is evidence the stated 25 mm fitted the fittings those buyers already had. It is not evidence that the pipe replaced a 32 mm or 40 mm basin waste. Henderson's chart puts 25 mm outside in the metric pressure column, not in domestic solvent-weld waste. It does not prove this listing is BS EN ISO 1452 pipe, and the listing does not claim it. Use the row when the fitting is about 25 mm outside, such as a pond filter socket of that size. Skip it for a 32 mm or 40 mm basin or bath, and skip it if you need 3 m.
eco-filtration eco-filtration 25 mm waste pipe

Testsieger

eco-filtration eco-filtration 25 mm waste pipe
8.4/10about £10.20
View offer

The short 32 mm and 40 mm sticks are not that system

Unifizz states 32 mm outside and 200 mm, at £8.89, and reviews call it too short. TOP-VIGOR states 40 mm outside and 0.35 m, at £8.89. Those titles are the outside diameter of a short sleeve, not nominal waste. A trade 40 mm solvent-weld pipe is about 43 mm outside in JDP's example. Neither stick states a socket. The pond fork is on flexible or rigid PVC pipe.

What not to claim from the title

Brett Martin can point to BS EN 1566-1 because that is their PVC-C waste in 32 mm, 40 mm, and 50 mm. eco-filtration does not print that standard, and neither do the short sticks. If you need a real 32 mm or 40 mm waste, buy a named system in that size, long enough for the branch. This set has no 3 m trade length. Cement steps stay on how to join PVC pipe.

Common questions

Is 25 mm outside diameter the same as 32 mm waste?
No. Nominal 32 mm solvent-weld waste is about 36 mm outside in JDP’s example for a typical UK system. eco-filtration states 25 mm outside. That is more than 10 mm smaller than the socket a 32 mm waste fitting expects. Reviews that say the joints fit are about fittings of the stated size, not about a basin waste you did not measure.
What outside diameter is 32 mm, 40 mm, or 50 mm solvent-weld pipe?
In JDP’s table, about 36 mm, 43 mm, and 56 mm outside for those three nominal sizes. Push-fit is about 34 mm, 41 mm, and 54 mm, and it does not cement into solvent-weld sockets. Measure the old pipe. A title that says 32 mm or 40 mm on a 200 mm or 350 mm stick here is stating that stick’s own outside diameter, which is a different convention.
Can this 1 m black pipe replace a basin waste?
Only if the waste you are replacing is actually about 25 mm outside and the run is within 1 m. B&Q treats 32 mm as the usual small basin size and 40 mm as the bath and sink size. This listing is 25 mm and 1 m. Being black does not make it that 32 mm branch.
Why are the 32 mm and 40 mm sticks not the waste pipes?
Unifizz is 32 mm outside and 200 mm long. TOP-VIGOR is 40 mm outside and 0.35 m long. A nominal 32 mm or 40 mm solvent-weld waste is larger outside than its name, and it is sold as a pipe system with sockets, not as a short sleeve. Reviewers of Unifizz say they bought it too short. Two reviews on TOP-VIGOR do not establish a waste system.
Does the listing comply with BS EN 1566?
The eco-filtration extract does not print BS EN 1566 or BS EN 1329. Brett Martin’s PVC-C waste does, in 32 mm, 40 mm, and 50 mm, because that is their stated product. You cannot move that claim across to a 25 mm listing that never names the standard. Approved Document H points at those standards for sanitary pipework. It does not certify an amazon.co.uk title.
What should I buy if I need a real 32 mm or 40 mm waste?
Buy a stated 32 mm, 40 mm, or 50 mm system from one range, long enough for the branch. This set has no 3 m trade pipe. Measure the old pipe, and do not cement this 25 mm length into polypropylene push-fit.

Related pages

Best PVC pipe

PVC pipe

PVC pipe buying guide: name the job before the price

Flexible or rigid PVC pipe: a coil, socket, or skip

How to join PVC pipe: waste, a duct, or clear tube

Sources

Public UK sources and the amazon.co.uk extracts used for this comparison. Retrieved 16 October 2026.

  1. Water Supply (Water Fittings) Regulations 1999 (retrieved 16 October 2026)
  2. Approved Document H: drainage and waste disposal (retrieved 16 October 2026)
  3. Approved Document F: ventilation (retrieved 16 October 2026)
  4. BS EN ISO 1452-2:2009, BSI summary (retrieved 16 October 2026)
  5. WRAS approvals directory, PVC section (retrieved 16 October 2026)
  6. Brett Martin waste FAQ (retrieved 16 October 2026)
  7. HSE CIS27: solvent ventilation (retrieved 16 October 2026)
  8. amazon.co.uk listings for the nine ASINs in this comparison (retrieved 16 October 2026)