Dishwasher Not Draining? Finding a pool of standing water at the bottom of your dishwasher after a cycle is one of the most frustrating appliance problems — especially when there’s no obvious blockage to explain it. The good news is that most dishwasher draining problems have a clear cause and, in many cases, a straightforward fix.

This guide covers the seven most common reasons a dishwasher won’t drain, what to try yourself, and when it makes sense to call an engineer.

Why Is My Dishwasher Not Draining? Introduction

When a dishwasher fails to drain, the fault is almost always in one of three areas: a blockage in the drainage system, a mechanical failure in the pump or motor, or a problem with the drain hose itself. The difficulty is working out which one — especially if you’ve already checked for visible blockages and found nothing.

Here are the seven most common causes, starting with the ones you can investigate yourself:

7 Reasons Your Dishwasher Won’t Drain (Including When There’s No Blockage)

Blocked or dirty filter

The most common cause of a dishwasher not draining is a clogged filter. Most modern dishwashers have a cylindrical filter at the bottom of the machine that traps food debris. If this hasn’t been cleaned regularly, it can become so blocked that water can’t pass through.

How to check: Remove the bottom rack, locate the filter (usually a twist-lock cylinder in the centre of the floor), and rinse it under warm water. A soft brush can help remove stubborn grease.

Blocked drain hose

The drain hose carries water from the dishwasher to your household drainage. If it has a kink, is clogged with grease, or has been incorrectly routed, water won’t be able to leave the machine — even if the filter is perfectly clean.

How to check: Pull the dishwasher out carefully and inspect the hose at the back. Look for sharp bends or blockages at the connection point to the sink or standpipe.

Blocked air gap or high loop

Many dishwasher installations include an air gap (a small device mounted near the sink) or a high loop in the drain hose. Both prevent contaminated water from siphoning back into the machine. If the air gap becomes clogged, or the high loop sags, draining is affected.

How to fix: Remove the cap from the air gap and clear any debris. For a sagging high loop, re-secure the hose so it loops above the cabinet base before descending to the drain.

Faulty drain pump or pump motor

If the filter and hose are both clear, the most likely culprit is the drain pump itself. The pump is a small motor-driven component that actively pushes water out of the machine. Over time, pumps can fail due to wear, or become jammed by foreign objects such as broken glass or grit.

Signs of a pump failure: you’ll often hear a humming noise during the drain cycle without any water movement. This is a repair that requires a professional engineer.

Faulty float switch or water inlet valve

The float switch monitors the water level inside the dishwasher. If it’s stuck in the ‘full’ position, the machine may believe it already has too much water and prevent more from being pumped in or out. A malfunctioning water inlet valve can cause similar confusion in the machine’s control cycle.

This is a less common fault but is more likely in older machines with mechanical float assemblies.

Clogged sink drain or garbage disposal

This one is easy to overlook: if your dishwasher drains into the same pipe as your kitchen sink, a partially blocked sink drain can prevent the dishwasher from draining properly. If your sink is slow to drain, fix that first — the dishwasher problem may resolve itself.

If you have a garbage disposal unit, also check that the knockout plug has been removed (a common installation mistake) and that the disposal itself isn’t clogged.

Control board or door latch fault

In rarer cases, the dishwasher’s electronic control board may not be sending the correct signal to initiate the drain cycle. This can be caused by a software error or a failing component on the board. A faulty door latch can also interrupt mid-cycle operation, leaving the machine with water inside.

A control board fault will usually produce an error code on the display. Check your machine’s manual or search the model number and error code online.

How to Fix a Dishwasher Not Draining? — Step-by-Step

Before calling an engineer, work through these steps in order:

Run a drain/cancel cycle — press and hold the cancel or drain button for 3 seconds. Some machines have accumulated mid-cycle water that a forced drain will clear.
Check and clean the filter — remove, rinse, and scrub the cylindrical filter at the base of the machine.
Inspect the drain hose — check for kinks, clogs, and correct routing behind or beneath the machine.
Check your sink drain — run the tap and confirm water drains freely from the kitchen sink.
Clear the air gap — remove the cap on the air gap fitting (if installed) and clean out debris.
Check for error codes — consult your manual and note any codes displayed on the control panel.
If none of the above resolves it, the pump or control board is likely faulty — this requires a professional repair.

Dishwasher Not Draining But No Blockage — What Now?

If you’ve worked through the filter, hose, and sink drain checks and everything appears clear, the problem is almost certainly mechanical or electronic:

Drain pump failure — the most common non-blockage cause. Replacing a pump typically costs £80–£150 including parts and labour.
Float switch stuck in the raised position — can be checked by gently pressing the float (usually a small dome on the dishwasher floor) to confirm it moves freely.
Control board fault — less common, but possible on machines over 5 years old. An engineer can run diagnostics to confirm.

In most cases, a pump replacement is a cost-effective repair. The decision to repair or replace comes down to the age of the machine and the overall repair cost — see our repair vs replace guide for guidance.

Is It Worth Repairing a Dishwasher That Won’t Drain?

As a general rule, if your dishwasher is under 7 years old and the repair cost is less than 50% of the cost of a replacement, repair is the better option. Dishwashers have an average lifespan of 9–12 years, so a mid-life repair usually represents good value.

For machines over 8–10 years old, or where the repair involves a control board replacement (which can cost £150–£250+), replacement may make more financial sense.

Our engineers can give you a fixed quote before any work begins, so you can make the decision with full information.

Still having problems? Book a dishwasher repair engineer today. Eco Repairs covers Romford, Ilford, and across Essex and East London. We offer same-day and next-day slots, and all repairs come with a 12-month parts guarantee. Call us: 0203 026 0534 | Email: bookings@ecorepairs.co.uk | Book online: ecorepairs.co.uk/contact-us

Dishwasher Repair Cost in the UK — What to Expect

Repair costs vary depending on the fault and your location, but here are typical ranges for dishwasher draining problems:

Fault type	Typical cost (parts + labour)	DIY possible?
Filter clean / drain hose clear	Free (DIY) or £60–£80 call-out	Yes
Drain pump replacement	£90–£150	Rarely
Float switch replacement	£70–£120	Possibly
Control board replacement	£150–£250+	No
Water inlet valve	£80–£130	Possibly

Frequently Asked Questions

Why is my dishwasher not draining but there’s no blockage?

If the filter and drain hose are both clear, the most likely cause is a failed drain pump. Other possibilities include a stuck float switch, a faulty control board, or an issue with the water inlet valve. An engineer with a multimeter can diagnose the exact fault quickly.

Can I fix a dishwasher that won’t drain myself?

Cleaning the filter and clearing a kinked drain hose are both DIY-friendly tasks. However, replacing a drain pump, float switch, or control board involves disassembling the machine and working near electrical components — we’d recommend calling a qualified engineer for these.

How much does dishwasher repair cost in the UK?

Most dishwasher drainage repairs cost between £80 and £150 including parts and labour. Control board replacements are more expensive at £150–£250+. At Eco Repairs, we provide a fixed quote before starting any work.

Is it worth repairing a dishwasher or should I replace it?

If the machine is under 7 years old and the repair costs less than half the price of a new dishwasher, repair is usually the better option. For machines over 10 years old, or where the repair cost is high, replacement may make more sense. Our engineers can advise you before committing to anything.

Why is there standing water at the bottom of my dishwasher?

A small amount of standing water (up to about an inch) at the very bottom of the dishwasher is normal — it’s there to keep the door seal from drying out. However, if there is more than an inch of water, or if water is visible above the filter level, your dishwasher has a draining problem.

Does Eco Repairs fix dishwashers in Romford, Ilford, and Essex?

Yes — we cover Romford, Ilford, Chadwell Heath, Hornchurch, Brentwood, and the surrounding Essex and East London areas. Same-day and next-day appointments are available. All repairs include a 12-month parts guarantee.

Can a dishwasher not draining damage the machine?

Yes, if left unresolved. Standing water creates the ideal conditions for mould growth and can cause the pump seals and door gasket to deteriorate faster. It’s worth getting the fault diagnosed promptly rather than leaving the machine standing with water inside.

Book a Dishwasher Repair in Romford, Ilford & Essex

Eco Repairs is a local appliance repair specialist serving Romford, Ilford, Hornchurch, Chadwell Heath, Brentwood, and surrounding areas. Our engineers are fully qualified and carry common dishwasher parts on the van, meaning most repairs are completed in a single visit.

Same-day and next-day appointments available
Fixed quotes before work begins — no hidden charges
12-month guarantee on all parts fitted
All major brands repaired: Bosch, Siemens, AEG, Hotpoint, Samsung, Zanussi, and more
Eco-friendly ethos — we always explore repair before recommending replacement

Related reading:

• Dishwasher Repair London & Essex

• Repair vs Replace — The 50/50 Rule Explained

Call us: 02030260534

Dishwasher Not Draining? 7 Causes & How to Fix It