Our shower has had the same pressure for 6 years. This week, the pressure has increased substantially. The water dept. checked our outside water pressure and it is normal. The rest of the water inside the house is normal also. Do you know what could be causing this?

Someone removed a restrictor?
A clog cleared?

That's about all I can come up with. Just in case it's not the shower head "water saver" what's the brand name of your shower valve? One handle? How old? Does it have skald-guard or pressure control? Back t6o you, Tom

Shower heads can be deceptive and appear to have more pressure. A few bits of scale can block some of the opening in the shower head so the remaining holes must carry the same volume as before which makes them appear to be stronger. Clean the head with a bag full of CLR or vinegar hanging on the head so the head is completely soaked over night. Or remove the head and disassemble the restricters and plates and clean them off.

Someone removed a restrictor?
A clog cleared?

We haven't removed anything. You move the single water lever to the left to turn it on... it does have a scald protector that is still working...

I think Ballengerb1 nailed it. Try cleaning the shower head, or just replace it. Do you not like the extra pressure?