Sizing a reverse osmosis (RO) system involves estimating your water usage and then choosing a system capable of producing significantly more than that amount per day.
1. Estimate Your Daily Water Usage
First, determine how much purified water your household consumes daily. A reasonable estimate for household water usage is about 75 gallons per person per day.
Example:
| Household Size | Estimated Daily Usage |
|---|---|
| 1 Person | 75 gallons |
| 2 People | 150 gallons |
| 3 People | 225 gallons |
| 4 People | 300 gallons |
| 5 People | 375 gallons |
Note: This is a general guideline. Actual water usage can vary based on lifestyle, appliance efficiency, and geographic location. Consider specific needs like filling aquariums, hydroponics systems, or other water-intensive activities when estimating.
2. Determine Required RO System Production Capacity
The RO unit should be sized to produce at least triple your estimated daily water usage. This is to account for factors like:
- RO System Efficiency: RO systems don't convert all water into purified water; some water is used to flush away impurities (the reject water).
- Peak Demand: You may need more purified water on some days than others.
- System Lifespan: Running a system at its maximum capacity constantly can shorten its lifespan. Oversizing gives you a buffer.
Example:
If a family of four uses an estimated 300 gallons of water daily, the RO system should be capable of producing at least 900 gallons per day (300 gallons x 3).
3. Consider System Specifications and Features
When selecting an RO system, also consider these factors:
- Recovery Rate: This specifies the ratio of purified water produced to wastewater generated. A higher recovery rate means less water is wasted.
- Tank Size: RO systems typically include a storage tank. Choose a tank size that meets your peak demand needs. A larger tank provides a buffer for high-usage periods.
- Stages of Filtration: More stages of filtration generally result in higher water purity. Typical systems include pre-filters (sediment and carbon) and a post-filter.
- Certifications: Look for certifications from organizations like NSF International, which verify the system's performance and safety.
In Summary: To size a reverse osmosis system, estimate your daily water usage (generally 75 gallons per person), then select a system that can produce at least three times that amount daily. Consider the RO system's recovery rate, tank size, and filtration stages for optimal performance.
