Over years of use, you get pretty familiar with how full your top load washer gets with water. This makes it pretty obvious when it is overfilling. Furthermore, if there is water spilling out over the top, that is a pretty obvious sign too. Of course, a washer overfilling is a very dramatic situation, but it is usually one your can fix yourself.
There are two main culprits that cause a washer to overflow – the water level switch and the water inlet valve. Before checking either, you should shut off the water to your washer via the shutoff valves at the water connection and unplug it.
These are general observations to apply to all brands and component issues can vary when reviewing a particular brand or model number.
Water Inlet Valve
If you notice that your washer is still filling with water even after you turned it off, this is a strong indicator of a problem with your water inlet valve. It is still letting water in from the connection, meaning it is not actually shutting. This means you will need to open the top of your washer – which may also mean removing your control panel depending on the model – and uninstalling the valve. Luckily, despite being such a crucial part, it is easy to uninstall.
Water Level Switch
When your washer fills with water, there is a pressure switch that, when activated, will shut off the flow of water. Essentially each cycle has a set amount of water and the switch will activate when it reaches that amount to prevent overfilling. A good sign that your water level switch has gone faulty is that it keeps filling even after unplugging your washer. While you can simply replace the part, there is also a chance that it just needs to be unclogged or the tube that is connected to the hose just needs to be reconnected. However, typically there is a reason that the part has failed, and if it happened once, it may happen again.