If she's having students in this office / workshop it becomes a business and not a hobby and you're facing the appropriate business legislaation
Just checked having done similar ourselves.
Any construction that comprises sleeping accom or appliances where by connection to a main sewer/drainage system is required will need building regulation approval.
Makes building a garden room a massive nightmare.
Aquaheat - you suggested a drinking dispenser but in my original message I mentioned dirty water so clearly you haven't read it!!
I've already said I need a tap and I won't be using much water. Water won't be particularly dirty (no food stuff and no solids). Drinking, hand rinse and water for massage and pedicure just looks nicer to pour from a sink than a jug. Also the physical sink could be used for very light rinsing and washing of equipment.
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local