J.F. Brondel invented the valve type flush toilet bathroom in 1738. Different parts of the bathroom were invented by different people so there is no special credit given to any person. A bathroom is a room which is included with a bath tub, toilet and Lavatory.
The concept of Bathroom itself can be dated back to the early 3000BC.
There are many patents granted to Thomas Crapper in the late 1800s for the flush toilet he designed or improved as he did not invent it from scratch. Alexander Cummings can be credited to have invented the first flush toilet for the Queen of England in 1775.
A Bathroom is typically equipped with a Bathtub, sink and a flushing toilet. When the bathroom was invented is hard to say as bathrooms were used as early as the 3000 BC. These might not have been our typical current day Bathrooms with a ll the amenities. Different cultures had different kinds of Bathrooms.
The toilet which is an integral part of the bathroom was invented by Thomas Crapper in 1800s. He modified the already existing flush which was patented by Alexander Cummings in 1775. He had 9 patents for the toilet flush that he improvised.
The concept of Bathrooms itself was different in the ancient times. The Roman civilization had elaborate thermal baths where people met for socializing and relaxation. The Mohanjodaro- Harappan excavations of 2800 circa show that the houses had bathrooms and lavatories that were built in the outer walls of the house which had plumbing with the water being drained to the outside in to a pit outside the house. In the later part of Reniassance is when the modern day bathrooms started popping up as there was more importance given to cleanliness and personal hygiene with the development in medicine, science and industries.