WSSC FY2027 Commercial Rates: ADC Tiers, Fixed Fees, and Unit Counts
WSSC Water’s FY2027 combined rates took effect July 1. See ADC tiers, meter-size AMF/IIF fees, mixed-use unit-count review, and a qualified bill model.
Direct answer
WSSC Water’s FY2027 combined rates for Montgomery and Prince George’s County accounts took effect July 1, 2026. Four progressive water-and-sewer tiers are $17.90, $20.02, $24.23, and $30.52 per 1,000 gallons, based on average daily consumption (ADC) per approved customer unit. Meter-size AMF/IIF charges stay fixed; unit-count credit requires WSSC review.
$17.90
Tier 1 combined
Per kgal through 80.9999 ADC
$30.52
Tier 4 combined
Per kgal above 275.9999 ADC
$458.33
2-inch ready-to-serve
Nominal quarter; actual fee is prorated
Review
Unit-count credit
Documentation and WSSC approval required
Official source facts
FY2027 combined rates took effect July 1
WSSC Water’s FY2027 schedule became effective July 1, 2026. The utility publishes water and sewer components separately and a combined rate for each progressive tier. The combined rates are $17.90, $20.02, $24.23, and $30.52 per 1,000 gallons.
Every monthly or quarterly bill also includes ready-to-serve charges. That means the variable rate table is not an all-in invoice, even when a property’s gallons and customer-unit treatment are known.
Progressive bill mechanics
ADC determines tier allocation; the top rate does not apply to every gallon
Average daily consumption, or ADC, begins with total gallons divided by billed days. WSSC’s progressive thresholds per recognized customer unit are 0–80.9999 gallons per day, 81–165.9999, 166–275.9999, and 276 or greater. Gallons are allocated across those bands rather than pricing the entire period at the highest reached rate.
Billed days matter because each daily threshold is multiplied by the number of days in the period. Customer-unit status can also change ADC for an account WSSC recognizes under its unit-count method. A model that omits either input can assign too many gallons to the higher tiers.
Mixed-use policy
Unit-count credit is reviewed, not automatic
WSSC says certain multi-unit residential and mixed-use multi-unit properties can use a unit-count process. The utility describes dividing total gallons by recognized units as a way to lower ADC and potentially the billing rate.
The review path requires a unit-count questionnaire, a reconciliation recap based on previous billing statements, and a current rent roll. WSSC reviews the account and applies a billing credit only if applicable. A property should not budget a credit or substitute its own unit count before that determination.
Fixed and other lines
AMF and IIF remain when consumption falls
Ready-to-serve charges contain an Account Maintenance Fee (AMF) and Infrastructure Investment Fee (IIF). Both rise with meter size and are prorated by billed days. The FY2027 nominal-quarter schedule totals $58.38 for a 5/8-inch meter, $458.33 for a 2-inch meter, and $2,064.57 for a 4-inch meter.
WSSC’s bill explainer also identifies the Maryland Bay Restoration Fund fee for commercial customers and says sewer charges generally follow water usage unless a submeter applies. This article uses the FY2027 combined water-and-sewer rates but excludes BRF, county stormwater, fixed charges, and other account-specific lines from the variable model.
Commercial implication
Large meters and shared accounts need two different audits
A high-use commercial property should first reproduce the progressive variable line from gallons, billed days, and the WSSC-recognized customer-unit count. It should then reconcile meter size and daily-prorated AMF/IIF as a separate fixed-cost check.
Mixed-use and multifamily teams have an additional documentation question: whether the account is eligible for WSSC’s reviewed unit-count treatment. Hotels, healthcare facilities, campuses, offices, restaurants, laundries, and other high-use properties still need the same progressive calculation, even when the unit-count path does not apply.
Smart Valve calculation — not a WSSC Water bill quote
A 90,000-gallon, 90-day progressive example
Assume a 90-day period, 90,000 gallons, and one assumed WSSC-recognized customer unit. The model applies FY2027 combined water-and-sewer tiers progressively. AMF, IIF, BRF, county stormwater, and other account-specific lines are excluded.
| Included line | 90,000 gal | 72,000 gal | Difference |
|---|---|---|---|
| Tier 1: 7.29 kgal × $17.90 | $130.49 | $130.49 | $0.00 |
| Tier 2: 7.65 kgal × $20.02 | $153.15 | $153.15 | $0.00 |
| Tier 3: 9.90 kgal × $24.23 | $239.88 | $239.88 | $0.00 |
| Tier 4: remaining kgal × $30.52 | $1,988.68 | $1,439.32 | −$549.36 |
| Combined variable total | $2,512.20 | $1,962.84 | −$549.36 |
The 90,000-gallon example allocates 7.29, 7.65, 9.90, and 65.16 kgal across the four tiers. At 72,000 gallons, Tier 4 falls to 47.16 kgal. A 2-inch meter’s posted AMF of $58.38 plus IIF of $399.95 equals a separate $458.33 nominal-quarter reference; the actual fixed charge is prorated by billed days and does not decline with use.
20% usage check
$549.36/90 days
Qualified 20% usage-reduction exposure
In the declared one-unit example, consumption falls from 90,000 to 72,000 gallons. All 18,000 reduced gallons come out of Tier 4, so the combined variable line changes by 18 kgal × $30.52 = $549.36 for the 90-day period.
Boundary: This is arithmetic, not a savings promise. Actual results depend on billed days, WSSC-recognized customer units, sewer/submeter treatment, and account details. AMF, IIF, BRF, stormwater, and other fixed or unmodeled lines stay outside this reduction figure.
Decision checklist
What to check first on the bill
- 1Record total gallons, the exact number of billed days, and the WSSC-recognized customer-unit count.
- 2Rebuild the four progressive allocations instead of applying the highest reached rate to every gallon.
- 3Confirm meter size and reconcile AMF and IIF using the billing period shown on the invoice.
- 4For an eligible mixed-use or multi-unit property, gather the questionnaire, reconciliation recap, prior bills, and current rent roll before assuming a credit.
- 5Separate BRF, stormwater, submeter treatment, and other account-specific lines from the combined variable-rate model.
Scope boundary
Where Smart Valve realistically fits
Smart Valve can be screened only against controllable metered volume and the usage-linked water/sewer lines that follow it. It does not change WSSC’s approved customer units, ADC method, meter size, AMF, IIF, BRF, or billing policy.
The generic calculator is directional because it does not reproduce WSSC billed days, progressive tier allocation, recognized units, or ready-to-serve charges. A property-specific assessment should begin with actual bills and WSSC account records.
Related commercial water decisions
Track Mid-Atlantic commercial utility changes
Follow adopted rates, fixed fees, billing policy, and regional cost signals.
Compare another adopted Mid-Atlantic commercial schedule
See how Arlington separates customer and usage charges.
Separate progressive, fixed, and policy-driven lines
Map each bill component before estimating controllable exposure.
Review the multifamily water-cost decision path
Connect unit records, common-area use, and account structure.
Prepare the bill and unit records
Collect meter, usage, billing-day, and customer-unit evidence.
See how Smart Valve qualifies estimates
Review source, assumption, and site-verification boundaries.
Frequently asked questions
What are WSSC’s four FY2027 combined water-and-sewer tiers?
Effective July 1, 2026, WSSC’s combined rates are $17.90, $20.02, $24.23, and $30.52 per 1,000 gallons across progressive ADC bands of 0–80.9999, 81–165.9999, 166–275.9999, and 276 or greater.
How does WSSC calculate ADC per customer unit?
WSSC begins with gallons divided by billed days. For an account recognized under unit-count billing, customer units also affect the average daily consumption used for tiering. Use the unit count WSSC recognizes, not an unapproved property estimate.
Is WSSC mixed-use unit-count credit automatic?
No. WSSC requires a questionnaire, reconciliation recap, current rent roll, and account review. The utility says it applies a billing credit only if the property is eligible after review.
Does lower consumption reduce WSSC AMF or IIF charges?
No. AMF and IIF are ready-to-serve charges based on meter size and prorated by billed days. They remain separate from the progressive usage calculation.
Primary source trail
Sources and retrieval details
Published: FY2027 schedule; page modified July 10, 2026 · Effective: July 1, 2026 · Retrieved: July 11, 2026
Controlling source for the four progressive water, sewer, and combined rates, ADC thresholds, effective date, and ready-to-serve requirement.
Published: FY2027 schedule; page modified July 10, 2026 · Effective: July 1, 2026 · Retrieved: July 11, 2026
Primary source for meter-size AMF/IIF schedules, nominal-quarter amounts, daily proration, and BRF context.
Published: Current policy; page modified June 4, 2026 · Effective: Current policy · Retrieved: July 11, 2026
Primary source for unit-count mechanics, mixed-use and multi-unit scope, required questionnaire/reconciliation/rent-roll documents, and non-automatic review.
Published: Current bill explainer · Effective: Billing-method guidance · Retrieved: July 11, 2026
Controls the billed-day and progressive-allocation method used in this model. FY2027 rate values come from the current FY2027 rate page, not the explainer’s older sample values.
Start with the WSSC bill, not a flat rate
Use the calculator only to screen metered-volume exposure, then submit the actual bill for assessment. It cannot reproduce WSSC billing days, recognized customer units, ADC allocation, AMF/IIF, BRF, or other account-specific lines.