I am working on project which aims at making a device which can calculate the amount of water flowing through the pipe (to calculate water usage by a user). The device will be connected to the main pipe line which goes to users house. The device should also be able to detect the leakages of water (even in droplets) and even scenarios like user forgot to close the Tap after use.
A thorough patent search is something even professionals need hrs for. The problem is that there might be many patents in that general direction. To do a complete search one needs the exact specifications of the invention (don't post them, that would destroy novelty and therefore patentability). And even professionals will never promise that they found everything. This question provides a good starting point: How can I perform a global patent search for free? Try different search terms. The claims of a patent describes its literal protection scope, the description helps with understanding them.