The 3 most common causes of a dishwasher not draining: (1) a clogged filter basket at the bottom of the tub — pull it out and clean it, (2) a kinked drain hose under the sink, or (3) a backed-up garbage disposal blocking the drain. Check these before calling a tech.
You open the dishwasher after a cycle and there's a pool of dirty, murky water sitting at the bottom. Your dishes aren't clean, the kitchen smells, and you're stuck hand-washing everything. A dishwasher that won't drain is one of the most common service calls we get at Treasure Coast Appliance Repair. The good news is that some causes are DIY-fixable. Here's what to check before calling a technician.
1. Clogged Filter or Food Trap
This is the easiest fix and the most common cause. Every dishwasher has a filter or food trap at the bottom of the tub, usually below the lower spray arm. When food particles, glass shards, label paper, or other debris accumulate in this filter, water can't drain. In Florida, we also see hard water mineral deposits clogging filters faster than usual.
DIY fix: Remove the bottom rack, twist out the filter (it usually turns counterclockwise), and clean it under running water with a soft brush. Do this every 2 weeks to prevent buildup. If you've never cleaned yours, prepare to be disgusted — it's probably coated in a thick layer of food sludge.
2. Garbage Disposal Connection Blocked
Your dishwasher drains through a hose connected to your garbage disposal (or directly to the drain pipe under the sink). If the disposal is full of food or hasn't been run recently, it can block the dishwasher from draining. This is especially common after big meals — Thanksgiving dinner, anyone?
DIY fix: Run the garbage disposal for 30 seconds with water running before starting the dishwasher. If you recently installed a new disposal, make sure the knockout plug was removed from the dishwasher inlet — we see this missed by DIY installers all the time.
3. Drain Hose Kinked or Clogged
The drain hose runs from the dishwasher to the disposal or sink drain. It can get kinked (especially if the dishwasher was recently moved or installed), pinched by the dishwasher being pushed too far back, or clogged with food and grease buildup. In Florida, we also see cockroach nests inside drain hoses — yes, really.
Check: Pull the dishwasher out slightly and inspect the hose for kinks. If it's clogged, a technician can disconnect and flush it, or replace it if needed.
4. Failed Drain Pump
The drain pump forces water out of the dishwasher and up through the drain hose. When it fails, the dishwasher fills and washes normally, but the water just sits there after the cycle ends. You might hear a humming sound as the pump tries to run but can't move water, or complete silence where the drain sound should be.
Repair cost: $175–$300 for drain pump replacement. This requires removing the dishwasher from the cabinet and accessing the pump underneath.
5. Check Valve Stuck Open or Broken
The check valve prevents water from flowing back into the dishwasher after it drains. If this valve fails, dirty water from the drain line can siphon back into the tub. You'll notice water appearing at the bottom of the dishwasher even when it hasn't been run. This is more of a plumbing issue than an appliance issue, but we see it frequently.
Florida-Specific: Hard Water and Drain Problems
Treasure Coast water is extremely hard — it's drawn from the Floridan Aquifer and contains high levels of calcium and magnesium. These minerals coat everything inside your dishwasher: spray arms, filters, drain lines, and pump impellers. Over time, this mineral scale restricts water flow and accelerates component failure. Consider using a dishwasher cleaner monthly to dissolve mineral buildup, and run a hot vinegar rinse cycle once a month.
Frequently Asked Questions
Why is there standing water at the bottom of my dishwasher?
Usually a clogged filter or blocked garbage disposal connection. Clean the filter first, then run the disposal before starting the dishwasher.
Can I fix a dishwasher that won't drain myself?
Clean the filter and run the garbage disposal first. If those don't work, the issue is likely a failed drain pump or clogged hose that needs a technician.
How much does dishwasher repair cost in Port St. Lucie?
Most drain repairs cost $125–$300. Filter cleaning $85–$150, drain pump replacement $175–$300, hose replacement $100–$200.
Dishwasher Won't Drain? We Fix It Same Day.
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