Bosch's manual answers a WAT28400UC owner who cannot see water in the drum directly: water cannot be seen in the drum because the water level in a high efficiency front-load washer is below the visible part of the drum, and this is normal, so no action is needed. A washer that really is short of water reports it as an error: the cold tap is off, the cold hose is kinked, the strainer is clogged or cold water pressure is too low, or E:93 for hot water. Bosch also says water does not appear to come in if Start/Pause is not selected or the supply hose strainers are clogged.
Differential
Likely causes of “Bosch 300 Series WAT28400 front-load washer uses very little water”, and how to tell them apart
- 1
Normal high-efficiency water level
What separates it Nothing is visible in the drum because of the normal high efficiency water level
How to confirm No action is needed, since this is the normal level
- 2
Taps off or hoses kinked
What separates it There is a slow fill and an error message because the taps are off or the hoses are kinked
How to confirm Turn on the taps and straighten the hoses
- 3
Clogged strainers
What separates it There is a weak fill because the strainers are clogged
How to confirm Clean the water inlet strainers, and then try again
- 4
Low water pressure
What separates it The fills are slow because of low water pressure
How to confirm Eliminate the cause, and check the pressure at the other taps
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether an error message showed on the display
- Whether the taps are turned on
- Whether the water can be heard entering
Try in this order
0 of 5 completedAccept the low water level
ReversibleIt is normal for the level to be below the visible part of the drum.
Check the taps and hoses
ReversibleCheck the taps and the hoses, with both taps on and the hoses straight, and then test again to see whether it helped.
Clean the strainers
ReversibleClean the strainers, at both the tap end and the washer end, and then test again to see whether it helped.
Check pressure
ReversibleCheck the pressure, by trying another tap in the house, and then test again to see whether it helped.
Read any message
ReversibleRead any message, since E:93 means that hot water is missing, and then test again to see whether it helped.
Model-specific
What is true of this model and not of its siblings
- Hard water and strainers
- Cleaning the water inlet strainers is recommended every 6 months in any event to reduce the chances of valve blockage in areas using hard water. A washer in hard water that has never had its strainers cleaned is a prime candidate for a slow or weak fill, and it costs only a pair of pliers and a few minutes to check.
- Extra Rinse and soft water
- Extra Rinse +1 or +2 is helpful for locations with very soft water or to generally improve rinsing results, allowing up to 2 additional rinses on selected programs and increasing program time. If rinsing looks poor because the water level looks low, Extra Rinse and less detergent are the right levers, not adding water by hand.
- Reading the drum through the glass
- Because the drum is horizontal, the water in a wash sits in the lower part of the tub below the door glass. Bosch's table lists this under water cannot be seen in the drum and says no action is needed. If you hear water entering and the display shows a normal cycle, the fill is working, and adding water or opening the door with water present is dangerous and unnecessary.
- Parts for this problem on the WAT28400 (RepairClinic, 2026-09-20)
- pressure sensor, part number 10009438, at $43.31; water inlet valve, part number 00635399, at $146.39.
- Other models this page answers
- These steps also fit the 300 Series WGA12400UC washer, 800 Series WAW285H2UC washer, 800 Series WGB24600UC washer.
Stop boundary
When this stops being a self-service repair
- !If an error message returns after the checks, call Bosch customer service on 1-800-944-2904
- !If the washer never fills, follow the fill page
Evidence ledger
Sources behind this answer
Bosch's own US owner-support pages for washer error codes and self-help.
Parts and list prices as shown on RepairClinic's parts search for this model number on 2026-09-20.
Exact questions
Common questions
Why can't I see water in my Bosch washer?+
The level in a high-efficiency front-loader is below the visible part of the drum; this is normal.
What does a weak fill suggest?+
A weak fill suggests clogged strainers or low pressure.