A stopcock is a tap or lock that stops the flow of water into your home.  It is likely that your building will have multiple stopcocks

to stem the flow of water to different vantage points. You may need this technique to stop the water if you have a leak, bust pipe or need to do repairs.

Ideally you will find a stopcock in the bathroom, kitchen, on external water storage tanks and at the main pipe leading into your home.

For instance, it is important to know the location of your stopcocks in an emergency.  You may have to stop the flow of water before a plumber or your water supplier attends to the problem.  There are a lot of reasons why a water tank leaks

With the introduction of new meters in some homes, the water supplier meter installation is outside the premises.  With the main stopcock situated close to the meter on the inside of the wall.

There are a few advantages to this new design

Access to the main stopcock into your home is now a lot easier

A stranger cannot stop water to your premises from outside your  compound.

This is a great starting point for your plumber to carry out any pipeline configuration you may need for your plumbing.

Security is increased as it is no longer necessary for your water supplier to enter your premises to read the meter.

The 2 main stopcocks type in use are the tap or lever and are shown below.

Think of your stopcock as a lock to allow or deny the flow of water.

Note that the plumbing configuration varies from building to building so you will find stopcocks used in different places. However, the concept is the same – to stop the flow of water when necessary.

For water storage tanks, you tend to have an inlet and outlet stopcock.  On one hand you have the inlet stopcock to stop the flow of water into the tank from a water source.  On the other hand, you have the outlet stopcock to stop water from flowing into your home

If you need your tank to be repaired or cleaned, it is important to shut the inlet stopcock to stop new water from filling the tank.

In some cases you may not be able to reach the tank due to its physical location.  An obvious reason is the water storage tank is elevated or in an inaccessible enclosure.

The best alternative will be to shut the water at the mains stopcock.