Calculate your CMWSSB bill
Chennai Metropolitan Water Supply and Sewerage Board Bill Calculator
Priced at CMWSSB's real domestic tariff
Estimated bill
₹336.00
- Water charge
- ₹180.00
- Sewerage charge
- ₹45.00
- Fixed charge
- ₹111.00
Cost composition — tap a segment to see what it is
Worked example
A 15 KL monthly CMWSSB bill (domestic) works out to ₹012345678901234567890123456789. That is ₹180.00 water charge + ₹45.00 sewerage + ₹111.00 fixed charge.
See the full breakdown ↓Have a fixed budget? Work backwards
Enter what you want to spend, and we'll tell you the maximum KL that stays within it — computed through the exact same CMWSSB tariff engine as the calculator above.
Budget → KL Calculator
Tell us your target bill, we'll tell you how many KL that buys
You can use up to
13 KL
for a monthly bill of ₹286.00 (within your ₹300.00 budget)
How to calculate your CMWSSB water bill
- 1Find your KL consumption from your meter or last bill.
- 2Select your connection type (domestic, or commercial/industrial where we have it) and meter size.
- 3Enter both into the calculator above.
- 4Get your itemised bill — water charge, sewerage and fixed charge.
Why most water bill estimates are wrong
They ask you to guess your own rate, or use a rough national average
Most water calculators either ask you to type in your own per-KL rate (accurate, but only if you already know it) or fall back to a generic property-type reference table that isn't tied to your actual board. Real municipal water tariffs vary a lot by board — as of today, PCMC's entry slab is ₹0.00/KL while CMWSSB's is ₹8.00/KL, computed live from our own tariff files, not invented for this page.
They skip the sewerage charge
Many quick calculators price only the volumetric water charge and drop the sewerage charge entirely — and because it's a percentage of the water charge (as high as 60% on some boards we've verified), skipping it can understate the real bill substantially, not just by a small flat amount.
They ignore billing-cycle differences
Some boards bill monthly and others bi-monthly — a generic calculator that assumes one cycle for every city will misstate your real bill by up to 2×. We always show the monthly-equivalent figure alongside the real cycle total, so you can compare fairly across boards.
The CMWSSB billing formula
The formula, in full
Water charge = KL consumed × slab rate per KL
+ Sewerage charge (25% of water charge)
+ Fixed charge (₹111.00/cycle)
= Total bill
Worked at CMWSSB's real slab rates: 25 KL priced through the slabs = ₹500.00 water charge, + ₹125.00 sewerage, + ₹111.00 fixed = ₹736.00.
This is the exact function and tariff our calculator uses for CMWSSB — not a simplified restatement. Water slabs are telescopic like electricity, unless a free-allowance threshold applies (see the free-rule section above, where relevant).
CMWSSB domestic water tariff
Tap or hover a segment for its exact rate.
Exact figures
| Slab (KL) | Rate (₹/KL) |
|---|---|
| 0–10 | ₹8.00 |
| 11–15 | ₹20.00 |
| 16–25 | ₹32.00 |
| 26–above | ₹51.00 |
| Sewerage charge | 25% of water charge |
| Fixed charge (15mm meter) | ₹111.00/cycle |
Effective from 1 April 2026 · Verified 2 September 2026 · source. SOURCED — taken directly from CMWSSB's own official tariff pages (cmwssb.tn.gov.in/tariff and /general-tariff), which independently converge on identical slab rates (₹8/₹20/₹32/₹51 per KL) and a 25% sewerage charge. Unlike DJB, CMWSSB does not tier its fixed/minimum charge by meter size — it publishes one flat minimum-monthly-charge per dwelling unit (the two official pages show ₹100 and ₹111 respectively; the higher, more specifically-dated figure is used here). That minimum is described officially as already including sewerage for near-zero consumption, so this model — which adds the 25% sewerage charge on top of the fixed charge for every consumption level, same as every other board here — may slightly overstate very-low-usage CMWSSB bills. CMWSSB is also mid-rollout on smart metering, so unmetered domestic connections may still be billed differently in practice (see the metering-status disclosure elsewhere on this page). Commercial/industrial tariffs not yet sourced — domestic only.
How CMWSSB compares to other water boards
The exact same 15 KL — priced at each board's real domestic tariff, computed live by this calculator's own engine. We only compare boards with a source-verified tariff on file, so this list grows as we add more:
| Board | Entry ₹/KL | Sewerage | Total (15 KL) |
|---|---|---|---|
| Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) | ₹8.00 | 25% | ₹336.00 |
| Pimpri Chinchwad Municipal Corporation (PCMC) | ₹0.00 | 15% | ₹52.79 |
| Delhi Jal Board (DJB) | ₹5.27 | 60% | ₹20.00 |
Why your water bill might be higher than your neighbor's
A different board — or a different meter size
Even a nearby address can be served by a different water board, and within the same board a larger meter size (used for bigger properties or bulk connections) carries a higher fixed charge. See the comparison above — the board and connection size both move the bill.
Crossed an all-or-nothing free threshold
Where a board offers a free-consumption scheme, it can be a cliff-edge, not a true allowance — using even 1 KL more than the threshold can make your ENTIRE consumption billable, not just the excess. See the free-rule section above if this applies to your board.
A larger household or more residents
More people at home directly means more KL consumed — showers, laundry cycles and dishwashing all scale with headcount, unlike a flat per-property estimate.
A possible leak or running fixture
A running toilet cistern or a slow tap leak can waste hundreds of litres a month without being obvious — if your bill jumps with no real change in usage, check fixtures and consider comparing two consecutive meter readings with all taps off.
Billing-cycle timing
If you're comparing your bill against someone on a different billing cycle (monthly vs bi-monthly), remember a bi-monthly bill covers roughly double the period — use the monthly-equivalent figure above for a fair comparison.
A different property type or connection category
Commercial, institutional or bulk (apartment) connections are often billed on a different tariff altogether from single-family domestic connections. If your household's overall utility spend feels high, it's also worth checking your electricity bill for the same kind of connection-category mismatch.
Your bill, component by component
A 20 KL example, broken into each charge — tap any line for what it is and whether you can influence it.
Water chargeReducible₹340.00+
Priced across telescopic slabs — the more you use, the higher the marginal rate. Cutting usage below your next slab threshold lowers this line directly. This example totals ₹340.00.
Sewerage chargeSet by board₹85.00+
A wastewater treatment and disposal fee, calculated as a fixed percentage of your water charge — it falls automatically whenever your water charge does, but the percentage itself is set by the board, not something you can change directly.
Fixed chargeFixed₹111.00+
Charged regardless of how much water you use, based on your connection's meter size (15mm). The only way to change this line is to change your connection's meter size or category.
Two worked examples — low vs high usage
A lighter 10 KL CMWSSB bill comes to ₹012345678901234567890123456789 — ₹80.00 water + ₹20.00 sewerage + ₹111.00 fixed.
A heavier 30 KL bill comes to ₹0123456789012345678901234567890123456789 — ₹755.00 water + ₹188.75 sewerage, since the higher slabs kick in well before 30 KL.
Estimated bill by household size
A relatable starting point if you don't have a meter reading handy yet — computed through CMWSSB's real tariff, using a common per-person usage benchmark.
| Household type | Est. monthly KL | Approx. monthly CMWSSB bill |
|---|---|---|
| Single occupant / bachelor | ~5 KL | ₹161.00 |
| Couple, no kids | ~9 KL | ₹201.00 |
| Small family (3-4 people) | ~16 KL | ₹376.00 |
| Large family (5-6 people) | ~25 KL | ₹736.00 |
| Joint household (7+ people) | ~36 KL | ₹1,437.25 |
Illustrative only, using a commonly cited ~4.5 KL/person/month domestic benchmark and CMWSSB's real tariff — not a verified per-household-type figure. Commercial, institutional and bulk-metered connections are billed on a different tariff not modelled here. Use the calculator above with your own meter reading for an accurate number.
Water consumption — quick reference table
| KL (per cycle) | ~Household size | Approx. monthly cost (DJB) |
|---|---|---|
| 5 KL | ~1 person | ₹10.00 |
| 10 KL | ~1 person | ₹10.00 |
| 15 KL | ~2 people | ₹10.00 |
| 20 KL | ~2 people | ₹10.00 |
| 25 KL | ~3 people | ₹199.76 |
| 40 KL | ~4 people | ₹656.64 |
| 60 KL | ~7 people | ₹1,359.52 |
Approximate figures at Delhi Jal Board's real rate, using a commonly cited ~4.5 KL/person/month benchmark, for quick browsing only — your own board's rate and household's real usage may differ; use the calculator above for your specific board.
CMWSSB water bill components explained
| Component | Charge type | What it is |
|---|---|---|
| Water charge | Telescopic, per KL | Your metered consumption priced through CMWSSB's slab rates. |
| Sewerage charge | 25% of water charge | Wastewater treatment and disposal fee — scales with usage, waived alongside the water charge if that's ₹0. |
| Fixed charge | Flat, per cycle | Covers connection and meter maintenance, charged regardless of usage — varies by meter size where CMWSSB tiers it. |
Tips to reduce your CMWSSB water bill
- Every KL you save lowers your bill directly, since billing here is fully volumetric with no free allowance.
- Fix dripping taps and running cisterns promptly — a slow drip can waste hundreds of litres a month unnoticed.
- Install low-flow fixtures on showers and taps for a real, ongoing reduction in consumption.
- Run washing machines and dishwashers full, not half-full, to get more use per KL billed.
- Check for a leak downstream of your meter if your bill jumps with no real change in usage.
- Compare your bill against the reference table above to see if your consumption is unusually high for your household size.
Piped water vs tanker/jar delivery
A real numeric comparison, not a guess — priced at CMWSSB's actual tariff against your own local tanker and jar prices.
Piped Water vs Tanker vs Jar — Cost Comparison
CMWSSB's real tariff against your own local tanker/jar prices
1 KL = 1,000 litres.
Check your local tanker operator's rate — this varies a lot by city.
Piped (CMWSSB)
₹336.00/mo
≈ ₹0.022/litre
Tanker only
₹2,400.00/mo
3 loads · ₹0.133/litre
20L jars only
₹45,000.00/mo
750 jars · ₹3.000/litre
Piped cost uses CMWSSB's real tariff via the same engine as the calculator above. Tanker and jar prices are your own local inputs — there's no centrally verifiable national rate for either, so enter what your area actually charges. Jars in practice aren't used to replace your entire monthly supply; this figure is a per-litre cost reference, not a realistic full-substitution scenario.
How municipal water tariffs are actually set
Unlike electricity (state electricity regulatory commissions) or gas (the PNGRB), there's no single central regulator that sets municipal water tariffs in India — each municipal corporation or water board sets and revises its own domestic tariff independently, sometimes with state urban-development department oversight. That's exactly why CMWSSB's structure can look completely different from another city's — different slab counts, different free-allowance rules, different billing cycles — and why finding a verifiable, consistently-published rate for every board is genuinely harder than it is for electricity or gas. We only publish a board here once we can cite a specific, dated source for it; see the citation on the tariff table above.
About Chennai Metropolitan Water Supply and Sewerage Board
Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) is the civic body responsible for piped water supply and sewerage services across Chennai. Like every municipal water board in India, it sets and revises its own domestic tariff — the slab rates, sewerage charge and fixed charges shown above are theirs, sourced and dated as shown on the tariff table.
Where your water comes from. Chennai draws from three surface reservoirs (Poondi-Cholavaram, Redhills, Chembarambakkam), Veeranam Lake (a dedicated 180 MLD pipeline since 2004), three seawater desalination plants (Minjur, and two at Nemmeli), and groundwater — a deliberately diversified mix because the city's reservoirs have run dry in past droughts. Source.
Water quality. CMWSSB treats to standard drinking-water norms, though residents on some desalination-fed zones (parts served by the Nemmeli plants) have reported higher-than-expected TDS in the past, which the board has attributed to RO membrane wear and addressed through membrane replacement — worth a basic filter if you notice a taste/hardness change.
Metering status: Only a small fraction of Chennai's roughly 7.7 lakh domestic connections currently have a functioning meter (CMWSSB cites just over 24,000) — most households are still billed the flat ₹111/month minimum shown on this page's tariff table, regardless of actual consumption. The slab-based calculator above reflects the metered tariff, which applies to your connection once it has a working meter — CMWSSB has announced plans to install roughly 1 lakh smart meters (about 73,000 for domestic connections) to expand real metered billing over time.
Independence disclaimer: DesiMetrics is an independent calculator and is not affiliated with, endorsed by, or operated by Chennai Metropolitan Water Supply and Sewerage Board or any government body. Figures here are estimates for planning purposes only — your official bill from CMWSSB is the authoritative source. Always cross-check against your actual bill or CMWSSB's own portal for billing or payment purposes.
How to check and pay your CMWSSB bill
Use the CMWSSB Online Water Tax Payment or the Metro Water app — CMWSSB's official app for bill payment and lodging complaints/grievances.
Your utility ecosystem
If your water bill went up, it's worth checking these too — a bigger geyser or more laundry cycles often shows up in both.
Water tank fill time
How long your tank takes to fill.
Electricity bill calculators
Real DISCOM tariffs for all 36 states.
Gas bill calculator
Same real-tariff approach for PNG.
Household bill builder
Geyser, washing machine — see what each appliance adds.
AC running cost
What your AC adds to your electricity bill.
Fuel cost calculators
Petrol/diesel, LPG cylinder and generator cost.
Financial calculators
GST, SIP, gratuity and tax-regime maths.
Delhi Jal Board
Water bill calculator for Delhi Jal Board.
Bangalore Water Supply and Sewerage Board
Coming soon.
Municipal Corporation of Greater Mumbai (Water Dept.)
Coming soon.
Related guides: understand your water bill
Standalone deep-dive guides on connection process and metering are on our roadmap — for now, each of these jumps to the relevant section on this page.
Frequently asked questions
How is my CMWSSB water bill calculated?
Your KL (kilolitre) consumption is priced through Chennai Metropolitan Water Supply and Sewerage Board's slab rates, plus a sewerage charge (25% of the water charge) and a fixed charge based on your connection's meter size.
What is a KL and how do I read my CMWSSB water meter?
A kilolitre (KL) = 1,000 litres, the standard billing unit for metered water supply in India. Most water meters display a running total in KL or cubic metres (the same unit) on a small odometer-style or digital display — subtract your previous reading from your current one to find your period's consumption.
Does CMWSSB offer a free consumption allowance?
Not currently, as far as we've verified — CMWSSB bills from the first KL at slab rates, with a flat minimum charge per connection. Some other Indian boards (like Delhi) do offer a free-consumption scheme; always check your own board's specific rules.
What is the sewerage charge on my water bill?
It's a charge for wastewater treatment and disposal, billed as a percentage of your water (volumetric) charge — currently 25% for CMWSSB. If your water charge is waived, the sewerage charge is too, since it's calculated off that base.
Does my meter size affect my fixed charge?
Yes — CMWSSB charges a different flat fixed charge depending on your connection's meter size (15mm), regardless of how much water you use.
Paani ka bill kitna aata hai ek normal ghar mein?
For a typical household using around 15 KL a month, expect roughly ₹336.00 on CMWSSB's real tariff — your actual bill depends on household size and your board's own rate. Use the calculator above for your specific number.
Is piped water cheaper than tanker or jar delivery?
Almost always yes, by a wide margin, when piped supply is reliable — use the piped-vs-tanker-vs-jar comparison above with your own local tanker and jar prices for an exact, computed answer rather than a generic claim.
How can I reduce my water bill?
See the "Tips to reduce your CMWSSB water bill" section above for the full list — the short version: fix leaks promptly, install low-flow fixtures, and every KL saved lowers your bill directly, since billing here is fully volumetric.
How do I check or pay my CMWSSB bill online?
Use the CMWSSB Online Water Tax Payment (https://cmwssb.tn.gov.in/online-water-tax-payment), or the Metro Water app — CMWSSB's official app for bill payment and lodging complaints/grievances.
How often is this calculator's tariff data verified?
We date every tariff figure with an effective-from and last-verified date (shown in the tariff table above and the footer of this page), and cite the source. CMWSSB's tariff was last verified 2 September 2026 — check that date against your own recent bill, since a rate change since then wouldn't yet be reflected here.
Is CMWSSB tap water safe to drink?
CMWSSB treats to standard drinking-water norms, though residents on some desalination-fed zones (parts served by the Nemmeli plants) have reported higher-than-expected TDS in the past, which the board has attributed to RO membrane wear and addressed through membrane replacement — worth a basic filter if you notice a taste/hardness change.
Where does my CMWSSB water actually come from?
Chennai draws from three surface reservoirs (Poondi-Cholavaram, Redhills, Chembarambakkam), Veeranam Lake (a dedicated 180 MLD pipeline since 2004), three seawater desalination plants (Minjur, and two at Nemmeli), and groundwater — a deliberately diversified mix because the city's reservoirs have run dry in past droughts.
Does this calculator apply to my connection if I don't have a working meter?
Only a small fraction of Chennai's roughly 7.7 lakh domestic connections currently have a functioning meter (CMWSSB cites just over 24,000) — most households are still billed the flat ₹111/month minimum shown on this page's tariff table, regardless of actual consumption. The slab-based calculator above reflects the metered tariff, which applies to your connection once it has a working meter — CMWSSB has announced plans to install roughly 1 lakh smart meters (about 73,000 for domestic connections) to expand real metered billing over time.
Paani ka meter reading kaise padhein?
Your water meter shows a running total in KL (or cubic metres, the same unit) on a small digital or odometer-style display — note the current reading, subtract your previous bill's reading, and the difference is your billing period's consumption in KL.
How we verify CMWSSB's tariff
How we verify every tariff
Source the order
We pull rates straight from Chennai Metropolitan Water Supply and Sewerage Board's tariff notification / gazette order — the primary document, not another calculator.
Cross-check the figures
Every slab, the 25% sewerage charge and every meter-size fixed charge for CMWSSB is encoded into a schema-validated file, so the maths is reproducible and auditable.
Publish with a date-stamp
Each calculator carries a verification status and last-checked date, linked back to its source order.