The Water Well Board suggests that the minimum water supply capacity for use inside a home should be at least 600 gallons within a two-hour period, or about 5 gallons per minute for 2 hours.Click to see full answer. Also to know is, what is a good well yield?5 gpm (two fixtures running simultaneously at 2.5 gpm) is a good estimate of peak demand, for the typical household. Water wells that reliably yield 5 gpm should be able to meet peak and daily needs for most residences. Wells yielding less than 5 gpm, however, are sometimes the only water source available.One may also ask, is 6 gpm good for a well? For most single-family homes, a minimum flow of 6 GPM is suggested from a well or spring. This flow would provide 360 gallons of water each hour, which would be sufficient to meet most home water peak demands. Similarly one may ask, is 4 GPM good for a well? Available water supply is a function of both the recovery rate and the storage volume of the well. Alternatively, the New Hampshire Water Well Association recommends a flow rate of 4 gpm for a period of four hours as an optimum water supply capacity for a private domestic supply.How many GPM Does my house need?For example, if you are running 2 showers at the same time, you will need 5 gallons of hot water per minute from the tankless water heater. If you were running a shower and the washing machine at the same time, you would need 4.5 gallons per minute from the water heater.