Holding Tank Sizing Calculator
Calculate proper holding tank capacity for your vessel
Holding Tank Requirements
Recommended Tank Size
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Daily Usage (per person)
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Total Daily Volume
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Base Requirement
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Safety Margin (20%)
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Tank Dimensions (approx)
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Tank Weight (full)
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Toilet Type Water Usage
| Type | Per Flush | Daily Est. | Notes |
|---|---|---|---|
| Manual | 0.5-1 gal | 3-4 gal | User controls water |
| Electric | 0.5-1.5 gal | 4-6 gal | Consistent flush |
| Vacuum | 0.3-0.5 gal | 2-3 gal | Most efficient |
| Composting | 0 gal | Urine only | Separate handling |
Marine Sanitation Guidelines
MSD Requirements
Vessels with installed toilets must have a Marine Sanitation Device (MSD).
Type III MSD (holding tank) is most common for recreational vessels.
Y-valve must be secured in NDZ (No Discharge Zones).
Best Practices
Use holding tank treatment chemicals to reduce odors.
Install tank level indicator for monitoring.
Consider deck pump-out fitting for convenience.