Watermaker Sizing Calculator

Size a desalinator for your cruising needs

Crew & Usage

Crew Size

Usage Level

Water Consumers

Pressurized Showers

Washing Machine

Dishwasher

Ice Maker

Tank & Production

Water Tank Capacity (gal)

Max Run Time (hrs/day)

Water Temperature

Watermaker Requirements

Recommended Capacity --

Minimum Capacity --

Daily Water Need --

Per Person Allowance --

Tank Days (no maker) --

Est. Power Draw --

Common Watermaker Sizes

Size (GPH)	Daily @ 4hr	Typical Boat
3-5 GPH	12-20 gal	Solo/couple, careful use
6-8 GPH	24-32 gal	Cruising couple
10-15 GPH	40-60 gal	Family, 35-45' boat
20-30 GPH	80-120 gal	Charter, 45-60' boat
40+ GPH	160+ gal	Large yacht, crew

Watermaker Considerations

Power Options

12V DC (small units)
Engine-driven (most efficient)
AC generator
Solar/battery for DC units

Maintenance

Pickle when not in use
Replace prefilters regularly
Membrane life: 5-10 years
Run at least weekly

Installation

Clean seawater intake
Adequate ventilation
Brine discharge below waterline
Pre-filter accessible