Direct answer
For the LG WT8405CW top-load washer, verify both water supplies, inlet screens, hose routing and the selected cycle before treating the inlet valves or pressure system as failed. First, open both faucets fully and note whether hot, cold or both are missing.
What this covers
- LG WT8405CW top-load washer (WT8405CW)
- LG top-load washer; ThinQ-enabled controls and menu paths vary by model.
- The specific fault this record addresses: will not fill with water or fills too slowly
What it does not cover
- ×The same symptom on a different LG product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
One or both supply faucets are closed or only partly open
What separates it No fill at all, or the machine fills only with cold or only with hot. Each temperature comes from its own hose and its own valve, so a single closed faucet produces a partial rather than total failure.
How to confirm Open both faucets fully and note which temperature is missing — that identifies which side of the supply to inspect.
- 2
The inlet screens are clogged with sediment
What separates it Filling is very slow rather than absent, often worse on one temperature than the other, and the machine may time out and report a fill fault.
How to confirm With both faucets closed and power disconnected, the small screens in the inlet valve ports are owner-cleanable on most machines. Sediment collects here after plumbing work or in hard-water areas.
- 3
A supply hose is kinked behind the machine
What separates it Slow or absent fill that began after the machine was moved, or after something was stored behind it.
How to confirm Pull the machine out far enough to see the full hose run rather than reaching blindly behind it.
- 4
The machine is filling correctly and the level only looks wrong
What separates it Water enters but never submerges the load, on a high-efficiency machine. This is by far the most common reason people report a fill problem on a modern washer.
How to confirm Watch whether every item becomes thoroughly wet and turns over during the wash action. If it does, the machine is working as designed — see not-level-water-too-low.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Whether no water enters at all, or water enters slowly, or water enters normally but to a level that looks too low.
- Which temperature is missing — hot, cold, or both — since each has its own hose, faucet and valve.
- Whether the door or lid lock indicator appears before the fill phase should begin.
Open both faucets fully and note whether hot, cold or both are missing
ReversibleThis identifies which supply side to inspect and rules out the most common cause in seconds.
Disconnect power and close both faucets before inspecting hoses and inlet screens
ReversibleNever work on an inlet valve with water pressure or power present.
Clear kinks and clean the owner-accessible inlet screens
ReversibleSediment in these screens is a common cause of slow filling, particularly after plumbing work or in hard-water areas.
Run a normal fill and confirm the water stops at the expected level
ReversibleOn a high-efficiency machine, the expected level is well below the top of the load.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- WT8405CW. LG top-load washer; ThinQ-enabled controls and menu paths vary by model.
- Type & capacity — TOP-LOAD
- 5.3 cu. ft. TOP-LOAD washer. The first thing to identify is whether your unit has a tall center AGITATOR post or a low-profile IMPELLER wash plate, because it changes correct loading and the 'clothes tangled / not cleaning' diagnosis: an impeller needs clothes loosely around the plate, not wrapped around a post.
- Motor — Direct Drive inverter (no belt)
- Belt-less Direct Drive inverter motor; noise/vibration is bearings and balance, not a belt.
- Top-load behaviour
- HE top-loaders use a low water level and sense the load, so 'the drum isn't full of water' is normal, not a fill fault. TurboWash 3D and ThinQ Wi-Fi feature on this tier. Lid-lock must engage before a spin; a spin that won't start is often the lid switch.
- Symptom boundary
- This record covers LG WT8405CW top-load washer when it will not fill with water or fills too slowly. A different symptom on the same hardware, or this symptom on a different LG product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !Close both faucets immediately for an uncontrolled fill, an overflow, or a leaking hose — do not wait to finish diagnosing.
- !Never probe or disassemble a live inlet valve with power connected.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. LG publishes this as "LG Washer - Troubleshooting Fills Too Slow / Does Not Fill". LG's own article for both halves of the symptom — no fill at all and abnormally slow fill. What that article does not carry is the model boundary — it is written for a product line, and WT8405CW is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
My LG WT8405 doesn't fill with much water.+
That is normal for a high-efficiency top-loader. It uses far less water than old machines and senses the load to add only what is needed, so you will not see the drum fill up — the clothes are cleaned by movement against the impeller or agitator, not by soaking. If it truly is not filling at all (a code, or bone-dry clothes), check the water supply valves and inlet screens.
The washer only fills with cold water, never hot.+
Each temperature comes from its own hose, faucet and inlet valve, so a missing hot fill points at the hot side specifically — check that the hot faucet is fully open and that the hot inlet screen is not clogged with sediment.
Barely any water goes in — is it broken?+
On a high-efficiency washer this is usually normal. These machines are designed not to submerge the load. What matters is whether every item becomes thoroughly wet and turns over during the wash action; if it does, the fill level is correct even though it looks wrong.
Does this answer apply to every LG model?+
No. It is scoped to WT8405CW. LG top-load washer; ThinQ-enabled controls and menu paths vary by model.
What should I record before troubleshooting not filling or slow fill or no water?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing not filling, slow fill, no water. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Close the faucets for an uncontrolled fill or leak; never probe a live inlet valve.
Answer for the exact device and software version shown above.