Need an affordable device to prevent tap leaks

Now a days, in India, almost all urban household use water flowing from tap. Ironically, due to high content of salt in the water, the tap starts leaking almost immediately. As the price of the tap is very high, user becomes resistent to replace it frequently and hence fresh water gets drained into the drainage system.

Should not we have a device such that after fitting it on the existing tap it creat vaccum inside, so that no water gets drained. The device should be cheap enough so every one can afford it.

I reside in Ahmdeabad, Gujarat State, and working with government organization.

Thanks and regards,

Nilesh Dharaiya