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Calcimator

RV Fresh Water Calculator

Estimate how many days your RV fresh water tank will last based on the number of people, shower frequency, and daily usage habits.

Inputs

gal
gal/day
gal/day

Results

Days of Water

2.1 days

Daily Usage

19 gal

≈ 4 buckets

Gallons Per Person/Day9.5 gal
Conservation Target12.9 gal/day
Refill Every2 days
How to Use This Calculator
  1. Enter your fresh water tank capacity (gallons).
  2. Set the number of people in your party and showers per day (each person).
  3. Enter cooking water and dishwashing water estimates per day.
  4. Review total daily water usage, days of supply in your tank.
  5. Reduce shower time to 3-4 minutes to dramatically extend your tank range while boondocking.

How the result changes with Tank Capacity

Tank CapacityDays of WaterDaily Usage
201.1 days19 gal
562.9 days19 gal
995.2 days19 gal
1367.2 days19 gal

What each input means

Tank Capacity
Your RV's fresh water tank size in gallons. Check your owner's manual.
Number of People
Total people using the RV's water system.
Showers Per Day (each person)
Number of showers each person takes per day. RV showers typically use 4 gallons with a low-flow head.
Cooking Water
Daily water used for cooking, coffee, and food prep.
Dishwashing Water
Daily water used for washing dishes. Hand-washing typically uses 2-4 gallons.

What each result means

Days of Water
How many days your tank will last at current usage rates.
Daily Usage
Total gallons consumed per day by all occupants.
Gallons Per Person/Day
Average daily water consumption per person.
Conservation Target
Reduce daily usage to this amount to gain one extra day of water.
Refill Every
How often you should plan to refill (rounded down for safety).

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Tank Capacity = 40, Number of People = 2, Showers Per Day (each person) = 1, Cooking Water = 2 = 5 input(s) provided
  2. Calculate Days of Water
    Days of Water
    2.1 = 2.1
  3. Calculate Daily Usage
    Daily Usage
    19 = 19
  4. Calculate Gallons Per Person/Day
    Gallons Per Person/Day
    9.5 = 9.5
  5. Calculate Conservation Target
    Conservation Target
    12.9 = 12.9

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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