You have a slow drain (constriction) somewhere after the shower drain and the washing machine drain join. Hence, the washing machine is feeding water into the "system" faster than the constriction allows it to flow to the sewer or septic, or whatever its destination is.
Does this only happen when the mashing machine runs ? Remember, your clothes washer can dump more water into the pipe than just about anything else in your house, including your toilet. The toilet, though it flushed quickly, only uses between 1.3 and about 6 gallons per flush, most recent toilets are in the 1.6 range, by law. Your washing machine on the other hand, it can empty the whole wash tun in about what, 30 to 60 seconds ?
Did this always happen, or has gotten worse recently ?
If it has been this way for years, it could be that the final drain is undersized, or possibly some semi-permanent obstruction in the drain from your house.
If it getting slowly worse, you need to have someone figure out what is blocking the pipe that far down, and get it cleared. Eventually, if it continues to get worse, it will overflow your shower basin.
The washing machine does not heat water. It brings hot water in from the hot water heater. They are usually hooked into the same water supply as your shower and sinks.
If the toilet and shower are in an upper floor then there is a PVC drain for both that will drain to either the sewer or septic. If there is a vertical piece to this, as there is in my basement, then you actually get some dribbling and running sounds from the water 'falling' down that vertical PVC. I get this same noise from the washing machine on the main floor draining down to the basement.
shower toilet washing hands dishwasher washing machine washing dishes (in sink) washing dog watering garden drinking cooking swimming pool bath
A shower curtain can often be cleaned simply by removing it and washing it in the washing machine. If one is concerned about using all natural products, there are many of these available for use in the laundry.
Yes, it is perfectly safe as long as you have ample water pressure. Contrary to my wife's beliefs, you can also run the washing machine and dish washer at the same time, too :)
Installing a steam shower in the basement is not a good idea. The steam shower should be installed in the nbathroom of your home.
It's nothing special. You can just put it in the washing machine, but put it on a delicate setting. Then hang dry. Do not put it in the dryer.
The best way to clean a bathroom shower curtain is to wash it in a washing machine with several towel in a cold water setting. You should then hang it outside to dry.
Stoppage
Use a shower instead of a bath Buy a new toilet if you have an old toilet Turn the taps off if they are not needed Fill the washing machine to the top
You can put it in the washing machine, but this may not be effective. Your best bet is to take it outside and use a hose or a low-pressure washer. You can also scrub it off with a toothbrush; that is always my method.
You can wash a shower curtain in the washing machine. Just pitch in a towel , add detergent, and wash it as you would any other load of laundry. Hang it back up in the bathroom and let it air dry.