Free planning tools · Plan servicing and costs

Toilet emptying-interval estimator

Estimate a liquid-container servicing range from your own daily volumes and a reserve allowance.

No account needed. Results update here as you change the inputs. Measurements stay in this tab unless you choose to share a link; shared links contain the inputs, including any location coordinates.

Your inputs

The starting values are examples. Replace them with your own measurements, prices or documented requirements.

What to have ready
  • The rated liquid-container capacity and chosen reserve.
  • Collected daily low and high volumes per user, including flush water if relevant.
  • The gap between your actual servicing opportunities.
Measurements for Toilet emptying-interval estimator

Calculated from your inputs

Your plan

The example will calculate here when JavaScript is ready.

What to do next

    Calculation details

    Inputs used in this result

    Compare a change before committing

    Keep this plan, change the inputs and see the difference. The comparison stays in this tab.

    Can the liquid container reach the next servicing opportunity?

    This emptying-interval calculator focuses on liquid storage. Enter the daily volume actually collected, a low and high planning estimate and an unused-capacity reserve. It then compares the high-use estimate with your intended gap between service opportunities.

    The required-capacity result makes a container comparison useful: keep the users and usage assumptions fixed, then see what the rated volume needs to be. It is not a universal claim about urine production or composting capacity.

    How to use this planner

    1. Enter collected volume assumptions and user count.
    2. Set the container reserve and planned service gap.
    3. Read the conservative interval and required rated capacity, then monitor the real container level.

    The calculation

    Usable volume = rated capacity × (1 − reserve). Earliest estimate = usable volume ÷ (people × high daily volume); latest uses the low daily volume.

    A worked example

    A 10 L container with 20% reserve and two users collecting 1–1.5 L each per day gives about 2.67–4 days.

    Example inputs are demonstrations. Replace them with your own measurements, prices or documented requirements.

    Assumptions and limits

    Example usage volumes are editable planning assumptions, not physiological estimates. Enter the volume actually collected in this container, including flush water if applicable. Check the level and service before full; round scheduling down. This liquid estimate does not calculate solids composting capacity. Solids service intervals, additives and treatment depend on the exact system; use its manual and monitor it separately.

    Questions about this calculation

    Can this estimate how often the solids container needs emptying?

    No. Solids handling, treatment and usable capacity depend on the exact system. Plan that separately from the liquid estimate using the model instructions and actual monitoring.

    What does a result below one day mean?

    Under the high-use assumption, the container reaches the reserved limit within that day. The page shows hours in that case; organise within-day checks and servicing rather than rounding it up to a day.

    Put the result in context

    Off-grid toilet chooser

    Compare toilet categories against your power, servicing and space arrangements using visible decision rules.