Sometimes, the problem with low water pressure is not with the pipes, but with the fixtures themselves. If your showerhead or faucet is clogged with mineral deposits or debris, it can restrict the flow of water. In this case, replacing the fixture or cleaning it thoroughly can help restore proper water pressure.
In some cases, low water pressure can be caused by issues with the municipal water supply. If there is maintenance being done on the water main or a water main break, it can cause a temporary drop in water pressure throughout the neighborhood. If you suspect that this is the case, contact your local water authority to get more information on any potential water supply issues.