rajhdeeprath, what you might ask is 'what is the best what to send a signal from the water tank on the roof of my 5 story building to a reciver in the basement ?
we would say, if you have a wifi signal, you can use 2 ESP8266 modules and use the wifi router. you do not need to get on the internet.
or, you might be able to use the 2 ESP8266 modules to talk to each other.
if you search for the module, and use the term wall
when you google : NRF24L01+ walls
what you will find is reports from others that 2 or 3 walls in a house will decrease the signal
most of us would offer to get one, and test it and report your findings.
another way, not mentioned is powerline transmission.
you can connect to the wires that run the pump and connect in the basement. the signals have some limitations, but should be directly connected to the main power panel. this is common and parts are available.
also not mentioned, what if your antenna was on the side of the building and your other antenna was on the outside wall so that they were in line of sight ?