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Tech supportSluice Sink Guide | DU, DUH & DUHS Explained
Sluice sinks are used in hospitals, care homes, nursing homes, hospices and other healthcare environments for the safe and hygienic disposal of body waste.
Also known as slop hoppers or hospital disposal units, sluice sinks incorporate a flushing disposal bowl connected to a manual cistern and drainage system.
Although the basic principle is straightforward, there are several choices to make when specifying a sluice sink. These include the size and configuration of the unit, top or back flush entry, left- or right-hand orientation, cistern type and drainage connection.
This guide explains the main options and how to choose the correct sluice sink for your installation.
Replacing an existing sluice sink?
Send us photographs, approximate dimensions and the position of the flush and waste connections and we can help identify the most suitable replacement.What is a sluice sink?
A sluice sink is a specialist sanitary disposal unit designed for the hygienic disposal of body waste in clinical and healthcare environments.
Typical uses include disposing of waste from:
- bedpans
- urine bottles
- vomit bowls
- drainage bags
The disposal bowl incorporates a full flushing rim. When the manual cistern is operated, water is released around the rim to rinse the bowl and carry its contents through the waste outlet into the drainage system.
The principle is similar to a conventional WC, but the appliance is specifically designed as a healthcare disposal unit.
Is a sluice sink the same as a slop hopper?
The terms sluice sink, slop hopper and disposal unit are commonly used to describe the same general type of sanitary appliance.
In healthcare specifications, however, you may also see the designations DU, DUH and DUHS. These identify different configurations of disposal unit.
![Diagram showing a sluice sink with manual cistern and 110mm spigot waste outlet]()
DU, DUH or DUHS: which sluice sink do I need?
One of the first decisions is how much functionality you need.
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DU – disposal unit
Choose a DU when you simply need a compact wall-mounted sluice disposal unit.
At approximately 600mm wide, this is the smallest of the three standard configurations and consists primarily of the flushing sluice bowl.
Best suited to: installations where disposal is required but additional sink or working space is not needed.
DUH – disposal unit with drainer
A DUH combines the sluice disposal bowl with additional stainless steel draining or working space.
At approximately 1000mm wide, it provides a larger work surface while remaining considerably more compact than a DUHS.
Best suited to: installations requiring a disposal bowl plus useful adjacent working or draining space.
DUHS – disposal unit with sink and drainer
A DUHS is the most complete configuration.
It combines:
sluice disposal bowl + separate sink bowl + drainer/work surface
within one unit.
Current H-DUHS models are approximately 1600mm wide and incorporate a central 500 × 400 × 200mm Grade 304 stainless steel sink bowl with a 38mm unslotted flush grated waste and no overflow. (We also supply 1200mm units incorporating sluice bowl and separate sink bowl for installations where space is limited).
Top entry or back entry?
The flush pipe connection must match the cistern arrangement. Top entry is normally selected for an exposed cistern, while back entry is normally selected for a concealed cistern within a service duct or behind the wall.
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Top entry
The flush pipe enters the unit from above and is typically used with an exposed cistern mounted on the wall above the sluice sink.
Back entry
The flush connection enters from behind and is typically used with a concealed cistern installed within a service duct, behind the wall or behind an IPS panel.Replacing an existing sluice sink?
Matching the existing flush arrangement is usually the simplest option unless the plumbing is being altered.Left-hand or right-hand?
Handing refers to the position of the sluice bowl when standing in front of the unit. This is important when specifying DUH and DUHS models, so always check the room layout, existing services and required workflow before ordering.
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H-DUHS-16-LH = left-hand sluice / centre sink / right-hand drainer
H-DUHS-16-RH = right-hand sluice / centre sink / left-hand drainer.Which cistern does a sluice sink need?
A complete installation requires a suitable manual flushing cistern.
The main options are:
Exposed stainless steel cistern
A robust, surface-mounted manual cistern for installations where the cistern and flush pipe remain visible.
Exposed plastic cistern
A surface-mounted plastic cistern typically used with a top-entry sluice sink.
Concealed plastic cistern
Installed within a service duct or behind a wall or panel and normally paired with a back-entry sluice sink.
The cistern, flush connection and sluice sink should therefore be specified together rather than treated as completely separate components.
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What waste connection does a sluice sink use?
Current Washware Essentials H-DU, H-DUH and H-DUHS sluice sinks use a 110mm plain spigot waste outlet.
P and S traps are available to suit the 110mm spigot and connect to standard 100mm soil pipework.
This is an important point when replacing an older sluice sink, as you should not assume that the dimensions or waste connection of an existing unit are identical to those of the current model.
Always check the current product drawing and the site's drainage arrangement before ordering associated fittings.
P trap or S trap?
The correct trap depends on the direction in which the drainage connection needs to leave the sluice sink.
P trap = horizontal outlet
S trap = vertical outlet
Both create a water seal between the sluice sink and drainage system, helping prevent odours from coming back through the outlet.
As a simple rule:
Drain goes into the wall → check whether a P trap is required.
Drain goes towards the floor → check whether an S trap is required.The actual site drainage arrangement and product drawing should always be confirmed before ordering.
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What are sluice sinks made from?
Washware Essentials H-Series sluice sinks are manufactured from Grade 304 stainless steel, selected for durability, hygiene and ease of cleaning in demanding healthcare environments.
Depending on the model, features include:
- smooth, easy-clean surfaces and detailing
- a full flushing rim
- pressed tops to reduce joints and welds
- folded safety edges and anti-drip detailing
- wall-mounting brackets
- optional front support legs
What is HBN 00-10 Part C?
HBN 00-10 Part C: Sanitary Assemblies provides guidance for sanitary assemblies used in healthcare facilities. It superseded the former HTM 64 guidance that may still be referenced in older specifications and product literature.
Washware Essentials H-Series sluice sinks are manufactured to meet the relevant HBN 00-10 Part C requirements as stated on the individual product specification.
Because project requirements and products can change, always check the current individual product specification and technical drawing when specifying equipment.
You may therefore encounter both an HBN designation and a Washware product code:
DU → H-DU
DUH → H-DUH
DUHS → H-DUHSWhat optional extras are available?
Depending on the model and installation, options can include:
- exposed stainless steel or plastic cisterns
- concealed plastic cisterns
- front support legs
- P or S traps
- trap strainers
- tap holes and compatible tapware
- grid or bucket-grating options where applicable
Check the individual product page for the options available with the particular model you're specifying.
Sluice sink specification checklist
Before ordering, work through these seven points:
1. Choose the configuration
Do you need a DU, DUH or DUHS?2. Check the available space
Typical widths are 600mm, 1000mm and 1600mm respectively.3. Select top or back entry
Top entry normally suits an exposed cistern; back entry normally suits a concealed cistern.4. Confirm the handing
For DUH and DUHS models, select the sluice bowl position that suits the room layout.5. Choose the cistern and trap
Match the cistern to the flush arrangement and the P or S trap to the drainage direction.6. Check accessories
Consider support legs, tap holes, gratings, cisterns and other optional equipment.7. Verify the current product drawing
Always check the current individual product specification before installation.Replacing an existing sluice sink?
If you're replacing an older sluice sink, don't rely on the old model name alone.
Before ordering, check:
- overall width and depth
- whether the sluice bowl is left- or right-handed
- whether the flush connection is top or back entry
- whether the cistern is exposed or concealed
- the waste outlet and drainage arrangement
- any tap holes, legs, gratings or other accessories required
Taking a few clear photographs can be particularly useful.
Send us photos of the existing installation, along with the approximate dimensions and the position of the flush and waste connections, and our team can help identify the most suitable DU, DUH or DUHS configuration.
Download our Sluice Sinks Explained guide
Need a reference you can save, print or share with colleagues?
Download our Sluice Sinks Explained PDF guide covering DU, DUH and DUHS configurations, top and back entry, handing, cisterns, traps and the key points to check before ordering.
Download the Sluice Sinks Explained PDF
Need help choosing a sluice sink?
Standard H-Series DU, DUH and DUHS models and variants are held in UK stock, including top/back-entry and left/right configurations where applicable, with delivery typically within 1–2 working days.
If you're unsure which model you need, contact the Washware Essentials team:
01275 400456
enquiries@washwareessentials.co.uk-
Posted by Paul Thorn
19th August 2026
