We have moved into an 18 years old house and when we moved in the hot water pressure was OK, not great but OK. With time it has gone bad. The hot water almost drips and we can only use one hot water tap else rest of the places so not get hot water.
Once for some plumbing repair we closed main water and once it was opened the hot water pressure was again as it was before. But with time it has again gone bad. Is it scales in the water heater ? The water heater is around 6 years old. Shall we drain water heater?
I would check the piping connections going into and from the heater as someone may not have installed a dielectric fitting to prevent electrolytic action from happening