This document discusses increases in water pressure from the 190 Building process pumps which has been contemplated for a range of pressures up to 550 PSIG. The existing process pumps are dual units, consisting of a steam turbine driven primary pump operated: in series with an electric driven secondary pump. The secondary pumps installed in 100-B, D, F, and H Areas were designed for 400 PSIG working pressure, and were given factory hydrostatic tests of 600 PSIG. The 100-DR pumps were given factory hydrostatic tests of 650 PSIG. The Ingersoll-Rand Company advises that a working pressure of 425 PSIG is as high as they would-recommend for pump casing pressure on the secondary pumps. In consideration of problems incident to increased operating pressures, the immediate limiting factor is the total head pressure permissible on secondary pump casings. Other limiting factors are filter plant capacities, and 183 process water capacities.