What this means on these models
Most leaks on the WAW line are not the tub. They are the door seal, the detergent drawer, a hose clip that has relaxed, or a drain hose that has been pushed out of its standpipe - all of them visible without taking the machine apart.
What you observe
- NEAR MISS - condensation under a machine in a cold room — A cold cabinet in a warm humid room makes its own water and no plumbing is involved.
- Water on the floor directly under the door after a wash — The classic door-seal position: the water arrives during the wash and stops when the drum does.
- Water tracking along the floor from behind to the front — The source is at the back and the destination is at the front, which is why the puddle position misleads so often.
- Foam and water at the detergent drawer during fill — Overdosing or a blocked drawer housing rather than a machine fault, and it is the easiest of these to fix.
- A puddle under the middle of the cabinet — Hoses, clips and the pump live there, and water travels along the base before appearing, so the exact spot is only a hint.
Ranked causes for these models
- Inlet hose union weeping at the tap — Under mains pressure all the time, so it leaks between washes as well as during them - a useful distinguishing feature.
- Internal hose clip relaxed with age and vibration — A drum machine shakes its own plumbing loose over years; clips at the sump and the pump are the usual ones to go.
- Pump housing or filter seat not sealing — Very often follows a filter clean where the cap went back cross-threaded or without its seal seated.
- Drawer housing blocked with detergent residue — Water backs up out of the drawer because the path into the tub has silted, and it presents identically to overdosing.
The diagnostic order for these models
- Watch a fill with the drawer open — Foam backing up is visible instantly, and it separates a dosing problem from a machine problem in one cycle.
- Open the filter and re-seat the cap properly — Worth doing after any filter clean, because a cross-threaded cap leaks on every drain from then on.
- Feel the inlet hose unions at the taps with a dry tissue — A weep under mains pressure shows on tissue before it shows on the floor.
- Note which step of the cycle the water appears on — Fill, wash and drain implicate different components, so the timing is worth more than the location.
What to do before you start
Safety
Pull the plug before you open anything, and leave the door lock alone. It holds the door shut while the drum is turning and while there is water in the tub; it is not the component to defeat to make a test easier.
Models in the WAW family
Reference| Model number | Family key |
|---|---|
| WAW28420AU | bosch:washer:waw |
| WAW28440AU | bosch:washer:waw |
| WAW285H1UC | bosch:washer:waw |
| WAW285H2UC | bosch:washer:waw |
| WAW28620AU | bosch:washer:waw |
| WAW28640AU | bosch:washer:waw |
| WAW28790AU | bosch:washer:waw |
Where the owner fix ends
Owner territory ends where the diagnosis needs a meter. If the checks in the order above leave you with a component that can only be tested electrically, that is the point to stop.
Other pages for this family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
