Water Charge Exempt Quantity Token Tool

Description

Set chargeable = max(0,withdrawal-exemptQuantity) when applyExemption is true, otherwise withdrawal; amount = chargeable*suppliedRate.

Environmental payment and credit arithmetic depends on eligibility, allocation, withholding and sign conventions. A supplied verification flag or accounting label does not establish that a payment, permit or credit is legally valid or actually available.

Set chargeable = max(0,withdrawal-exemptQuantity) when applyExemption is true, otherwise withdrawal; amount = chargeable*suppliedRate.

When to use this tool

Use Water Charge Exempt Quantity Token when checking a specified allocation, charge or payment balance.

How to use the tool and how it works

Enter withdrawal, exemptQuantity, suppliedRate, applyExemption. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read chargeable, amount. Use the output convention below.

Require nonnegative withdrawal, exemptQuantity and suppliedRate. Set chargeable = max(0,withdrawal-exemptQuantity) when applyExemption is true, otherwise withdrawal; amount = chargeable*suppliedRate. Use one quantity basis and currency per that quantity unit.^[1]

Input field	Meaning and units	Accepted input
withdrawal	Withdrawal	Required. Finite number; minimum 0.
exemptQuantity	Exempt Quantity	Required. Finite number; minimum 0.
suppliedRate	Supplied Rate	Required. Finite number; minimum 0.
applyExemption	Apply Exemption	Required. Boolean.

Output field	Interpretation	Returned shape
chargeable	Chargeable	Required. Finite number.
amount	Amount	Required. Finite number.

json

{
  "input": {
    "withdrawal": 100,
    "exemptQuantity": 20,
    "suppliedRate": 2,
    "applyExemption": true
  },
  "output": {
    "chargeable": 80,
    "amount": 160
  }
}

Limitations and assumptions

The exemption is a supplied policy choice and unused exemption does not create a credit. No actual tariff, withdrawal right, tax treatment or legal eligibility is determined.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Review the applicable agreement or program rules and reconcile the full ledger before treating a calculated amount as payable or saleable.

References

Calculation and input contract: environmental-economics/water-charge-exempt-quantity-token — tool.io

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