Your washing machine may be a free-standing appliance, but it depends upon your plumbing system for proper operation. Issues with the water supply lines are problems for a plumber to address, not an appliance repair technician.
1. Stuck Taps
Most washing machines are fed by two taps or water valves -- a hot water valve and a cold water valve. In most cases, these taps are left open at all times so that water can freely flow into the washing machine during normal operation. If a tap gets stuck, you won't be able to close it or open it for the installation of a new machine or replacement hose. Sometimes you can force the tap open by lubricating it and then tapping it with a hammer to get it to move, but care must be exercised so the valve handle isn't broken. Generally, the best option is to have a plumber repair or replace the stuck valve.
2. No Hot Water
Equally as frustrating is when there is no hot water flowing into the machine even though the valve is open and you are using the proper settings. Although the problem is sometimes an issue with the appliance, it is just as likely that a broken diverter inside the assembly is preventing the water flow from switching from cold water to hot. The diverter is designed to switch back and forth between hot and cold as demand from the appliance varies. It should also be able to open only partially so that warm water can be delivered. If it gets stuck in a single position, you won't get flow for any temperature other than the stuck position. Replacement of the diverter solves the problem.
3. Line Leaks
Leaks from the hoses connecting the water valves to the machine or from the water lines that feed the valves are a major problem that can lead to water damage in the home. Most washers are connected by rubber hoses, which can wear out and crack over time. Frequent inspections can ensure that they are replaced as soon as you notice wear and long before a leak occurs. Water lines can also come loose at the joints or develop holes, so these should be inspected at least annually. If your machine is frequently off-balance or doesn't sit level on the ground, the harsh vibrations during operation can speed up damage to the hoses and lines.
Contact a plumbing company if you continue to have issues with the plumbing systems that attach to your washing machine.