Hard water per se won't be the issue. However, depending on your source and plumbing you will likely accumulate visible particles that can sometimes become obstructive. How much and how often depends on many factors that are likely unique to your particular situation. Soft water users get this, too, but typically not as much.

Soft water typically does this less because the media in the softener itself acts to "filter" many of these particles before they enter the household lines.

In any event, It's typically an easy thing to accomplish. Those little filter screens are common/cheap at the hardware store so if you don't want to mess with cleaning the things you can just replace them. That way you get a new gasket out of the deal, too.

@ kcred

If you have copper plumbing upstream of your machine, yes you are at a higher risk of deposits being caught in the filter screen. Limescale deposits will build-up inside your copper pipes, and after a while some of that calcium will flake and chip off as the water moves through the pipes. Calcium can also build-up on the filter screen itself, impeding water flow.

Citric acid, which can be purchased in your supermarket dishwasher detergent aisle under the name Lemi Shine, is excellent at de-scaling as is CLR. CLR is a much stronger product, but will make calcium foam and disappear in front of your eyes.

Yep, copper pipes upstream of the washer. Guess I'll pull the hoses and install new filter screens. Thanks to all for the info.

Since you're going to do it anyway, please do disconnect both ends of the hose. Most installs I've seen have a screen at the supply end plus another one at the machine-connection end. Can't speak to your install, but I'd check 'em both.

kcred,

The screens at the machine end are typically inside the water valve ports. Some are metal, some plastic. Most can be pulled for cleaning but can be tricky to do so without damaging them, particularly metal screens.

Thanks again everyone.
I'll be putting in new filter screens at the supply end of the hose today. As I'm well aware of my mechanical aptitude limitations, I'm gonna stay away from the machine end screens.
Thanks very much, and I'll let you know if the screens I replace were overly cruddy.
kcred

The valve screens may *need* to be cleaned if they're clogged. Cleaning/replacing only the faucet-end screens won't get you back to full flow if the valve screens are clogged.

The filter screens on the supply end looked okay. The gaskets were hard and really compressed. So I changed them out for new ones. I didn't look at the valve screens at all.
kcred