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You have 3 options to enjoy our latest catalogue. You can view it digitally online, download it in PDF format or you can request a printed copy to be sent to you.




For spares enquiries please contact our authorised spares reseller, Plumbers Mate.


International Distributors

Not in the UK?

This website contains the complete range of McAlpine products available in the United Kingdom. McAlpine also exports specifically designed products for use in over sixty countries worldwide via a network of agents and distributors, a selection of which are below. If you have any other queries relating to our export specific products then please contact us


  • Traps

  • What diameter and depth of seal should my traps have?

    Building Regulations state that appliances that are connected to a soil pipe should comply with the following table.

    Appliance Diameter of Trap (mm) Depth of Seal (mm of water)
    Wash basin*
    32 75
    40 50
    Foodwaste disposal unit
    Urinal bowl
    Washing machine
    Dishwashing machine
    40 75
    * The depth of seal may be reduced to 50mm if basin is fitted with spray taps and a flush grated waste without a plug.
    **Where these appliances discharge directly to a gully the depth of seal may be reduced to not less than 38mm.
  • Why do McAlpine make traps with 19mm water seal and where can they be used?

    Current building regulations state the minimum depth seal for traps should not be less than 38mm. However, 19mm water seal traps have been manufactured to meet the demand for replacement traps where the original shallow seal traps were installed prior to the current regulations.

    It is not uncommon in older properties for the waste from baths or showers to have shallow seal traps and discharge into an open hopper head. New 19mm water seal traps are often used when replacing the sanitaryware in these properties. This practice does not comply with current building regulations and they could be rejected if the installation comes under the scrutiny of the local authority building control officer.

  • What are the flow rates of McAlpine Shower Traps?

    Flow rates vary depending on the type of waste outlet and the head of water over the waste. The configuration of the discharge pipe work will also have some effect. However, McAlpine 50mm water seal shower traps have flow rates varying from 20 to 50 litres per minute with a 15mm head of water over the waste outlet and when tested under controlled conditions. All traps meet the minimum requirements of BS EN 274-2:2002.

  • Why do I get dirty water from the sink in my washing machine?

    Check that hose discharge from washing Machine loops up above the minimum height as specified by the machine manufacturer and at least to the underside of the work top for an inset sink before connecting into the sink trap.

    See installation details for washing machine traps.

  • The inlet nut of the trap will not tighten on to my waste outlet?

    The chances are that your waste outlet is of continental manufacture and not compatible to BS Trap inlet nut. Use [T12A-F] fitting on 40mm or [S12A-F] fitting on 32mm waste outlets to convert connection back to a compatible thread.

  • There is a smell coming from my showerwaste, what is wrong with the trap?

    Drain smells can enter the dwelling under certain conditions, to ensure this is not happening check that the right trap has been installed i.e is it minimum 50mm water seal?

    Has the 'O' ring on the dip tube been damaged?

    Is the dip tube correctly positioned within the trap?

  • Why does water not run away in my shower?

    If it is not due to the obvious reason of a blockage caused by a build up of debris, the problem could be due to backpressure within the discharge pipe. This can be because at some point the discharge pipe has retained water, which is preventing air from flowing freely through the pipe. A plumber should check the installation.

  • What is the difference between an anti-syphon trap and a re-sealing trap?

    A re-sealing is designed to allow air to pass through the water seal under negative pressure but will retain sufficient water to ensure the minimum depth of seal is retained. Whereas an anti siphon trap has a small mechanical valve which opens under negative pressure. Both versions will break the syphonic action thus protecting the water seal. Note. the re-sealing trap may be noisy.

    For more details see relevant pages on web site or catalogue.

    View anti-syphon and resealing traps.

  • When should I use an anti-syphon or re-sealing trap?

    Generally when the waste pipe or discharge pipe from an appliance is beyond the limitations of an unvented waste pipe. Usually more critical on basin and bidet wastes.

    View anti-syphon and resealing traps.

  • My shower tray is too thick to take the waste on your 90mm shower traps. What can I do?

    Our 90mm shower traps accommodate varying maximum shower tray thicknesses, depending on the model. Should you have an enquiry regarding a specific model, then please contact us If you are using a [ST90CP10], [ST90CB10] or [ST90WH10] you can purchase an extended locking nut which will accommodate trays up to 25mm thick.

    Click here to view accessories

  • Can MacValve or a non- return valve be used in line with macerator units (e.g Saniflo)?

    No. Some Saniflo unit installation instructions state that MacValve or Non-return valves can be used in conjunction with the unit, however our products cannot accept the 10 Psi pressure from these units and are therefore not suitable for use. We suggest you contact Saniflo, or the macerator manufacturer, to discuss alternative options. 


Where to Buy

McAlpine products are available from all national and most independent plumbers and builders merchants. If you are having trouble locating a stockist near you then please fill out the form below and we’ll endeavour to respond as soon as possible.

Contact Us

McAlpine plumbing products are designed and manufactured to be installed by qualified plumbing professionals. On this basis we cannot accept installation queries from the general public. Please contact your local McAlpine stockist or a qualified plumbing professional. For all other enquiries please fill out the form below.

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