Quick Answer
To calculate the flow rate for whole house water filters, divide the total home water usage in gallons per day by the filter's service time in days. This will give you the gallons per day (GPD) flow rate. Consider factors like filter replacement interval and system pressure drop.
Determining Total Home Water Usage
To calculate the flow rate, start by determining your total home water usage in gallons per day. This can be found on your water utility bill or estimated based on average usage rates (80-100 gallons per person per day). For a family of four, assume 320-400 gallons per day.
Calculating Filter Service Time
Next, determine the recommended filter service time, usually measured in days or hours. Typical values for whole house filters range from 1,000 to 15,000 gallons or 3 to 30 days. For example, a filter with a 1,500-gallon service time will need to handle 320 gallons per day for a family of four.
Applying the Flow Rate Calculation
Now, divide the total home water usage (320 gallons per day) by the filter’s service time (1,500 gallons) to get the flow rate. This yields a flow rate of approximately 0.21 gallons per minute (GPM) or 12.6 gallons per hour (GPH). Consider system pressure drop, filter size, and flow characteristics when selecting a filter to ensure it meets your home’s requirements.
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