I got my hot water heater replaced this morning. Immediately after the water pressure in my toilet became very high. When flushed it’s so forceful I jump. I noticed a noise when the guys were still here and they said it was the toilet refilling after they turned the water off. But it hasn’t gotten better through the day. Did I just not realize my pressure was sluggish before? The other tank was about 7/8 yrs old and had a a tiny leak and some rusting.
Try running the water for several minutes, both hot and cold sides, at the other fixtures too. Do they behave similarly? Do the symptoms diminish after a minute or two?
When a water system is opened, especially for something like a heater replacement, air gets into the pipes. Eventually the air finds its way out through the various faucets. As bubbles of air exit the faucet they make a lot of noise. They also can cause the water to eject forcefully. It sounds and looks a lot like the water pressure had been increased even though that's not actually the case. Running the faucets for a few minutes allows the air to be purged from the system and it'll behave normally again afterward.
I experienced something similar. I installed a new and more efficient water heater. In doing so, I had to replace some of the old iron pipes. Suddenly, I no longer have water pressure problems with the shower hot water which is understandable, but the toilet starting filling and flushing better too!