Water Tariff Slabs and Minimum Charge: A Worked Example

A slab tariff charges a different rate for each band of water used, and a minimum charge sets the least a connected household pays even if it uses little or nothing. These are the two rules that cause the most confusion in a khanepani upabhokta samiti, usually because members work them out differently. This article explains the logic in general terms. The actual slabs, rates and minimum charge must come from your own constitution (bidhan) and the decisions of your general assembly, and local-level rules may also apply.

Why committees use slabs

A flat rate per unit is simple, but it does not discourage waste. A slab tariff keeps the first band of water cheap, so basic household needs are affordable, and raises the rate for heavier use, which pays for the extra pumping, treatment and pipe wear. Committees also use slabs to give a fair deal to small households while heavy users, such as a guest house or a dairy, contribute more.

The two common ways to apply slabs

There are two methods, and your committee must say which one it uses.

1. Progressive (incremental) slabs. Each band is charged at its own rate. Units in the first band at the first rate, the next units at the second rate, and so on. This is the most common and the fairest.
2. Whole-bill slab. The rate of the highest band reached applies to all units. This produces sudden jumps and more disputes.

Write the method into the minutes. A treasurer who changes mid-year will otherwise apply the other method without anyone noticing.

A worked example (illustrative only)

The numbers below are an example to explain the method. They are not a recommended or official tariff.

Band (units per month)	Example rate per unit
First 10 units	10 rupees
Next 10 units (11 to 20)	15 rupees
Above 20 units	25 rupees

Suppose the example minimum charge is 150 rupees a month and a household used 24 units.

• First band: 10 units x 10 = 100
• Second band: 10 units x 15 = 150
• Third band: 4 units x 25 = 100
• Water charge = 350. This is higher than the minimum of 150, so 350 applies.

A household that used 8 units would have 8 x 10 = 80, which is below the minimum, so the bill would be the minimum charge. Under the whole-bill method the same 24 units would all be charged at 25 and give a very different figure. This is why the method matters.

What the minimum charge really covers

A minimum charge recognises that the committee has fixed costs whether or not water is drawn: pipeline maintenance, tank cleaning, the caretaker's wage and electricity for pumping. Some committees fold meter rent or a maintenance fee into the minimum. Others show it as a separate line. Decide which approach you use and print it clearly on the bill so a household can see how the total was reached.

Also decide what happens when a household is disconnected or away. Does the minimum continue, stop or reduce? That rule belongs in your bidhan or in a recorded decision, not in a treasurer's memory.

Common mistakes in tariff calculation

• Mixing methods. One collector uses progressive slabs while another charges the whole bill at the top rate.
• Applying a new tariff to old readings. A tariff changed in Kartik should not alter bills for Ashwin.
• Forgetting the minimum. Low-use households are billed for actual units when the rule says minimum applies.
• Rounding differently. Decide whether to round each slab or the final total, and to which rupee or paisa.
• Penalty on penalty. Charging a late fee on previous late fees without a rule that allows it.
• Not showing the workings. A household that cannot see the calculation will assume it is wrong.

Households with special situations

Real schemes have exceptions, and the tariff should say how to treat them before an argument starts. Examples include a shared tap serving several families, a school or health post with its own category, a shop or hotel with higher use, a household with a leaking pipe after the meter, a house locked for months and a meter that has stopped. For each, the committee can decide a rule: a separate category with its own slabs, a fixed monthly bill, an average of previous months or a waiver after inspection. Write the rule in the minutes, apply it the same way each time and record the reason on the household ledger.

Recording tariff changes properly

Recording tariff changes properly

When the general assembly changes the tariff, record four things: the date of the decision, the effective date, the old and new slabs and where the decision is minuted. A good system keeps both tariffs with date ranges so a bill from last year can be reproduced exactly. In paper registers, put a dated note on the first page and start a new column set.

Before applying a new tariff widely, calculate ten sample households under old and new rules and present the differences to the committee. This avoids surprises and shows members that the change is fair.

How software handles it

In Khanepani Upabhokta Samiti Software, the slabs, method, minimum charge, fixed fees and penalty rules are entered once as the committee's tariff with an effective date. Every household's bill is then produced from the same rule and the bill shows each band, so the household sees how its total was reached. If you also run an irrigation or micro-hydro scheme with similar billing, look at user committee software as well.

Next step

Write your tariff in one table: bands, rates, method, minimum, fixed fees, penalty and effective date. Check it against your bidhan and the last assembly minutes. Then send it to WebsNP on WhatsApp at +977 9846280400 and we will show how the bill appears in the system, so you can confirm it matches before you commit.

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