sudden increase in water usage

Underground leaks are not uncommon. Turn off all taps and check the meter to see if it's still moving.
It's also possible, but less likely, someone has tapped into your supply.
Last up - someone at the water company has made a mistake (Accidentally or deliberately)

Maybe a defective toilet tank buoy. The valve not closing well and there´s a silent leak...

robal

"It's also possible, but less likely, someone has tapped into your supply."
That is not unknown here in the Philippines.

FindlayMacD wrote:

"It's also possible, but less likely, someone has tapped into your supply."
That is not unknown here in the Philippines.

I agree with this, I will make a further check on this if someone has tapped my water.

You have this problem in Hamilton, Ontario, Canada?

mugtech wrote:

You have this problem in Hamilton, Ontario, Canada?

All she has to do is observe or look if her neighbor in Hamilton has a garden becoming greener all the time with a proportionate increase in her H2O consumption!

robal wrote:

Maybe a defective toilet tank buoy. The valve not closing well and there´s a silent leak...

robal

Yes. A silent leak is not easy to detect. This could be bad flap.
The float may need adjustment or valve gone bad, you will hear hissing sound in this case.

To check for a silent leak from your water closet tank don’t flush the toilet for approximately 15 minutes and then put in about 10 drops of red food colouring or until the water in the tank gets red. Leave sit and check to see if there is a red water line in the bowl. If you do than you have a faulty flapper in the tank.

Another problem could be in the tank is the overflow tube. The automatic water shutoff valve (ballcock) might need adjusting or replacing. To check remove the lid of the water tank and check to see if water is overflowing in the overflow pipe.

Close all spigots on the property, including the toilet tank supply valve.  Go look at your meter. is it still registering some usage.? If so, you have a hidden/concealed leak.  Get the blueprint and try to map where all the pipes are. Check buried pipes first, connectors, look for signs of dampness, If it still not found, you might need to break into the system at various places and cap pipes, create zones. Not an easy job. wish you luck.