lol. there is not going to be any washrooms or water sources while you are out in the back country.
For washrooms, its going to be like back in the old days i.e. just go out and find a secluded place, away from the camping area and take care of the business. Usually its a good habit to carry a handy shovel with you, dig a small pit in the ground and close it after using it.
For water, people usually bring portable water filters and purify lake water and use it.
Hope this helps!

Pack a small trowel.  There are likely “thunderboxes” on the campsites, an outhouse without the house part.  Drop the lid to learn how it got that name.  If you really need to go and aren’t near a thunderbox, a cathole 6″ deep for your poop.
Hand sanitizer.  Travel sizes fit in the TP tube.
Pristine is a $20 option for drinking water.  Mix 5 drops from bottle A & 5 from bottle B, let sit for 5 minutes, add to a L of water, wait 15 minutes.  Cheaper than a $100+ filter and never hurts to have in your daypack.  
I hear Bon Echo is a great place to get started.  Have fun!

https://www.sail.ca/en/platypus-ens-complet-gravity-works-2l-97231 I’ve been loving this filtration system

Pack a water filter or chemical water purifiers treatments for backcountry use and a small trowel for digging catholes or use the provided thunder boxes. Don’t forget to pack toilet paper and hand sanitizer

Thank you!! Your tips really helped me for first backcountry camping..!! I will come back with a feedback and hope you guys have wonderful summer..!