A valve’s maximum backwash rating describes a component under stated conditions. It does not tell you how much water your well and pump will deliver at a proposed filter inlet.
Read the condition attached to the rating
Pentair lists a maximum backwash flow of 7 GPM at a 25 psi pressure drop for its Fleck 5600 electromechanical filter valve. Its Fleck 2510 listing states 17 GPM at the same pressure-drop condition. These are component specifications. Neither number is a measurement of your household supply. Sources: Fleck 5600 and Fleck 2510 (checked 6 October 2026).
Separate three questions
Supply: what sustained rate reaches the intended inlet at the relevant pressure? System demand: what does the assembled system require for its media and configuration? Component limits: can the valve and drain arrangement carry that demand under their stated conditions?
A hypothetical comparison
Suppose a complete-system manual requires 6.5 GPM under conditions comparable to your measurement, while you observe only 5 GPM. A valve with a higher capacity does not eliminate the supply shortfall. The numbers here are an illustration, not a specification for a particular filter.
The decision to carry forward
Keep the complete-system manual and measurement record together. Use the observation worksheet and then the bounded flow comparison. A favorable comparison still leaves chemistry, service flow, and installation checks.