You open the dishwasher and there’s a pool of dirty water sitting in the bottom. A Thermador that won’t drain is usually a clog you can clear yourself — and knowing where to look saves a service call.
Standing water that won’t clear? Call 844-975-6696 or book a visit.
Quick guide
| What you’re seeing | Likely cause | Fix it yourself? |
|---|---|---|
| Water sitting after every cycle | Clogged filter | Yes — clean it |
| Won’t drain since a new disposal | Disposal knockout plug left in | Yes — remove the plug |
| Drain hose kinked or blocked | Restricted hose | Often — check the hose |
| Pump hums but no drain | Jammed or failed drain pump | Partly — clear debris |
A little water is normal
A small amount of clean water in the filter well is normal — it keeps the seals from drying out. The problem is a pool of dirty water covering the bottom after a cycle, which means the drain path is blocked somewhere between the filter and the sink.
What causes it
- Clogged filter. Food debris in the bottom filter is the most common cause — and the easiest fix.
- Disposal knockout plug. After a new garbage disposal is fitted, the drain won’t work until the plug is removed.
- Kinked or blocked drain hose. A pinched or clogged hose stops water leaving.
- Jammed drain pump. Glass, a seed, or debris stops the pump — you may hear it hum without draining.
- Blocked air gap or sink drain. The shared sink line or the air gap on the counter is clogged.
Left standing, that water starts to smell — if yours does, see dishwasher odors once it’s draining again.
Step-by-step: what to check
- Run the garbage disposal. The dishwasher often shares its drain — clear the disposal first.
- Clean the filter. Twist out the bottom filter, rinse it, and clear the well underneath.
- Check for a new disposal. If one was just installed, confirm the knockout plug was removed.
- Inspect the drain hose. Look for kinks where it runs to the sink cabinet.
- Look for debris at the pump. With the water bailed out, clear anything stuck in the sump.
- Test the air gap. If there’s one on the counter, pop the cap and clear any gunk.
When to call a technician
Book a visit soon if the filter, hose, and disposal are all clear and it still won’t drain, or the pump hums without moving water. The drain pump is tested for continuity and checked for a jam before replacement — and in an apartment, a dishwasher that backs up or overflows can reach the unit below, so it’s worth sorting quickly.
It can wait if clearing the filter or disposal fixed it — that’s routine maintenance. If the pump itself has failed, book Thermador dishwasher repair.
What the repair actually involves
A technician bails and inspects the sump, clears any blockage, then tests the drain pump for continuity and free movement. A jammed pump is cleared; a failed one is replaced — a defined part in the least-expensive to mid category. If the blockage is in the home’s plumbing or air gap, that’s addressed instead. The main cost driver is a simple clog versus a pump. You get a written estimate before any work, and common drain parts are stocked for a single visit.
Is it safe to leave until then?
Bail out the standing water rather than leaving it — it turns stagnant and smells within a day, and a full tub risks spilling onto the floor. Once it’s empty, the dishwasher is safe to leave unused until it’s fixed. In a condo, don’t run it again until it drains, to avoid an overflow reaching a neighbor.
Preventing it
- Scrape plates before loading so less food reaches the filter.
- Clean the filter every few weeks.
- Run the disposal before starting a cycle.
Frequently asked questions
Q: Is standing water in the bottom of my dishwasher normal?
A: A little clean water in the filter area is normal and protects the seals. A pool of dirty water covering the bottom after a cycle is not — it means the drain is blocked, usually at the filter, hose, or pump.
Q: How do I drain my dishwasher manually?
A: Line the floor with towels, then scoop out as much water as you can with a cup and sponge the rest from the sump. That lets you reach the filter and pump to find the blockage — and stops the water going stagnant.
Q: Why won’t my dishwasher drain after a new garbage disposal?
A: Because the disposal’s knockout plug is likely still in place. New disposals ship with a plug where the dishwasher hose connects, and it has to be knocked out during installation or the water has nowhere to go.
Q: How often should I clean the dishwasher filter?
A: Every few weeks for most households, more often if you don’t scrape plates first. A clogged filter is the number-one cause of poor draining and of dishes coming out dirty, so it’s the easiest habit to prevent both.
Get it draining again
If the clogs are clear and it still won’t drain, the pump needs testing. We handle Thermador dishwasher repair with a written estimate before any work starts.
Call 844-975-6696 or book online. Same-day service is usually available in New York, Los Angeles, Chicago, San Francisco, Houston, and Miami.