Where does my water come from in Northern Ireland?

Since blue-green algae was first seen in Lough Neagh this summer, people around Northern Ireland have worried that their tap water might not be safe to drink.

Some have posted pictures of cloudy water online, while many more have googled the simple question: "Where does my water come from?"

For those whose water does come from the lough, NI Water are keen to reassure the public that it is safe and has been treated.

Where does my water come from?

As you can see on our map above, for many of us, including everyone in counties Tyrone and Londonderry, and most people in County Down, our water is not from Lough Neagh. It's from other lakes and reservoirs, including Lough Erne and Silent Valley.

If you're in Belfast, the line dividing lough water from non-lough water is squiggly: Scroll down for a close-up map of Belfast.

If you're still not sure, you can put your postcode in to NI Water's own postcode checker: Putting the name of your "water treatment zone" into your search engine will then show what source your tap water comes from.

Is my water safe to drink when there's algae in Lough Neagh?

This isn't the first year that toxic cyanobacteria - or blue-green algae - has been present in Lough Neagh, and NI Water says its filtering systems are designed to take that into account.

A spokesman said: "NI Water's number one priority is the quality and safety of your drinking water.

"We can assure our customers that the water supplied from all our Water Treatment Works, which includes water abstracted from Lough Neagh, is safe to drink and use as normal."

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You obviously shouldn't drink water straight from the lough - and should keep dogs and other animals away when the algae is there.

But by the time it gets to your tap the water has been through purification; NI Water says it uses several kinds of filter - including granular-activated carbon - and adds ozone, which neutralises biological matter.

Chlorine is also added to the water to make sure it is safe to drink.