You’ll need to connect your pressure washer to a water source. Most often, that source will be an outdoor tap, and you’ll use your garden hose to connect the tap to the pressure washer. Most pressure washers require a garden hose that’s less than 50 feet long and with at least a ¾-inch inside diameter.  If you don’t have access to an outdoor water tap, you still have options. One is to use the water tap for your washing machine. Those taps are threaded the same as an outdoor hose tap, so you’ll be able to hook up the hose without need of an adapter. You can also use a kitchen or bathroom sink. But as these are not threaded for hose attachments, you’ll need a threaded adapter sized for the tap as well as your hose. When using an indoor tap, you’ll need to run your garden hose inside through a window or door, so plan accordingly.