The short answer
A Costway dishwasher that finishes full is nearly always obstructed somewhere between its sump and the kitchen waste, and the pump itself is the least likely part of that path. On this class the usual cause is a portable machine draining into a sink above the pump's lift, with a filter and sump packed with debris next to rule out.
What you actually observe
- Water stays in the tub whenever the hose is on the taller sink — The hose height is the variable that changed.
- A smell of stale water when the door is opened — Water standing after every cycle turns within a day or two.
- NEAR MISS: water on the floor rather than in the tub — That is a leak and it has its own page and its own cause list.
The causes, most likely first on this brand
- A portable machine draining into a sink above the pump's lift — Ranked first on a Costway unit: a portable machine discharges over a sink edge, and a sink higher than the pump can lift is the commonest reason one of these leaves water in the tub.
- A filter and sump packed with debris — Everything the machine washes off collects in the sump, and a filter that has never been cleaned eventually holds enough to stop the pump drawing anything at all. Ranked second here: a small filter fills quickly in a compact tub.
- The drain hose kinked or crushed behind the machine — Ranked third here: a hose coiled and uncoiled for every wash takes a set and kinks where it was stored.
- A cycle stopped before it reached its drain — Ranked fourth here: last, and water after an interrupted cycle is a state rather than a fault.
Check in this order, and why this order
- Look at how high the hose sits above the machine — A pump on this class has a modest lift and a high sink asks for more than it has.
- Lift the lower basket out and twist the filter assembly free — A filter solid with debris explains both the standing water and the poor results before it.
- Look under the sink and follow the drain hose along its run — A flat section or a tight bend is visible and it explains everything.
What an owner can safely check
- Hook the hose over a lower point and secure it so it cannot fall out mid-cycle — A hose that slips out floods the floor as well as failing to drain.
Tools: cable tieAbout 15 min
- Take the filter out, clear the sump by hand and rinse everything under a hot tap — Refit the filter locked home, because one left loose lets debris straight into the pump.
Tools: brush, hot water, glovesAbout 25 min
- STOP HERE if the next step needs a meter on live terminals or a panel off — That is where an owner check ends and a service call begins.
Before you open anything
Safety
Switch the machine off at its breaker before reaching into the sump, because the heating element in the floor of the tub stays hot long after a cycle and the pump can start under power. Broken glass in a sump is the usual reason people cut their hands on a dishwasher, so wear gloves and use a torch. Scoop standing water out rather than tipping the machine.
When to call a technician
Call once the filter, the sump, the hose and the kitchen waste are all clear and water still stands in the tub, because a jammed or failed pump means the machine pulled out. Call sooner if the machine trips its breaker while trying to drain, since a stalled pump draws heavily. Bear in mind when you decide that parts for a value import are not stocked locally and a replacement unit can cost less than a part plus a labour call.
Nearest pages of this class
What this page does not cover
This page covers the Costway dishwasher as a class, not one family or model line. Pump types, hose routes and filter designs all change from build to build and are deliberately not here. Where a family or model page exists for your machine, it is the more specific answer and the one to read first.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
