Water Softener Sizing Calculator
Size water softeners based on hardness and household demand
Water Quality
Moderate hard: 7-10, Hard: 10-15, Very Hard: 15+
Add 4 GPG per 1 PPM of iron for total hardness
Household Information
Leave 0 for auto (75 GPD/person)
System Preferences
Leave 0 for auto based on fixtures
Water Softener Requirements
Required Grain Capacity
--
Recommended Unit Size
--
Daily Grain Removal
--
Compensated Hardness
--
Daily Water Usage
--
Required Flow Rate
--
Salt per Regeneration
--
Note: Size based on 7-day regeneration for efficiency. More frequent regeneration wastes salt; less frequent may cause hard water breakthrough.
Standard Softener Sizes
| Grain Capacity | Resin (cu ft) | Typical Use |
|---|---|---|
| 24,000 | 0.75 | 1-2 people, low hardness |
| 32,000 | 1.0 | 2-3 people |
| 40,000 | 1.25 | 3-4 people |
| 48,000 | 1.5 | 4-5 people |
| 64,000 | 2.0 | 5-6 people, high hardness |
| 80,000 | 2.5 | Large home, very hard water |
| 96,000 | 3.0 | Commercial/large family |
Flow Rate by Resin Volume
| Resin (cu ft) | Service Flow (GPM) | Peak Flow (GPM) |
|---|---|---|
| 0.75 | 4-6 | 7 |
| 1.0 | 5-8 | 10 |
| 1.5 | 7-10 | 12 |
| 2.0 | 10-14 | 15 |
| 2.5 | 12-17 | 18 |
| 3.0 | 15-21 | 21 |
Water Hardness Scale
| Classification | GPG | PPM (mg/L) | Description |
|---|---|---|---|
| Soft | 0-3 | 0-60 | No treatment typically needed |
| Slightly Hard | 3-7 | 60-120 | May benefit from softening |
| Moderately Hard | 7-10 | 120-180 | Softening recommended |
| Hard | 10-15 | 180-250 | Softening highly recommended |
| Very Hard | 15+ | 250+ | Softening essential |