Romola
If you have a smart meter, use it to check how much electricity your washing machine uses and expect them to pay. Now that water is also expensive, you could work out the cost of that too.
And you could ask them to buy their own laundry detergent too.
I am not going to join the discussion about how often to change clothes.
Last Sunday, with 8 hours free electricity, I did several lots of washing, including a very hot one, used the tumble drier, batch cooked meals in the air fryer and soups in the soup maker for this week, ran the dishwasher and then with a cleaner, , showered long and luxuriously, charged all our devices including the portable chargers and hoovered the bedrooms. (Of course the fridge &freezer were still running in the background.)
According to the before/after readings of the smart meter, I’ll get a whole £2.50 refund.