I'm looking to build a small affordable bathhouse to go on my lake lot.. All I need is a shower sink and toilet, it cal be all in one room but I plan on doing it myself and need some ideas of materials that will be cheap and blueprints.. Thank you all
Since you chose not to add at least the state you live in when filling in your profile, no mention of town or city sewer, It's hard to say.
There is not going to be a "set of plans" you going to have to adapt something that works for you.
Most likly your going to have to get permits for something like this.
Sewer, water, electrical all will require permits.
May want to just pick up a book on basic shed plans or check on line under pool bath house.