We needed to replace the seats, etc. in the pipe that goes up to the shower head in the OLD cast iron bath tub. Some of the tub plumbing problems have been fixed/updated over the years. The new faucets control both the shower & the bath but there is a handle that diverts the water to the shower with the diverter handle between the cold & hot water faucets., We thought the plumber had just replaced the shower head & had so little pressure but was told, no, both the shower head & the pipe going to the shower also has a low flow feature mandated by law now nationwide? (The bath tub faucets have normal flow). I am sure I must waste just as much water showering now with the low flow feature than before without it as I have to leave the water on so much longer! I may switch to using the bath tub for baths & will surely use more water that way?! Is this now a nationwide law that they all have to be low flow? We tried making the holes in the shower head face larger but pressure the same... as I guess the low flow feature is in the tub to shower diverter?

Is there a way to get around this problem?