Steps Ventures · municipal wastewater lagoons · plain-English reference
Four thousand five hundred towns run a wastewater lagoon. Almost nothing written for them is written without something to sell.No vendor. No product. No performance figure.
The population
In EPA’s own inventory, across 46 states.
Fifty-nine percent serve under a thousand people.
Eighty-six percent are permitted under 0.5 MGD.
A floor, not an estimate. Section 3 explains why nobody can give you the real number.
A town this size has no staff engineer, usually one certified operator covering water and wastewater both, and a rate base that cannot absorb seven-figure debt service without a grant on top. Everything below follows from those three facts.
Contents
Five things that survive contact with the whole record.
02Including one that cost us a headline figure.
03Ten options, cheapest first, no product names.
04Read off 39 state funding lists.
05Three widely repeated details are wrong.
06Aimed at the supplier, the engineer, and the state.
07Including what this page deliberately does not contain.
01 · The short version
You are the normal case, not the edge case.
The median lagoon serves 773 people and runs 0.11 MGD. Ninety-four percent serve under ten thousand. Nobody builds a conference track around you. That is a marketing problem, not an engineering one.
A low ammonia exceedance rate usually means nobody measured.
Michigan files 1.1% against 12.7% nationally, because most of its lagoons sit on a permit where ammonia is reported and never limited. You cannot exceed a limit that is not there.
Most lagoon projects are small.
Across 21 states with comparable reporting, 217 state revolving fund projects name a lagoon. The median is $1.5M and 60% land under $2M. You are not automatically shopping for a new mechanical plant.
Almost nobody is funding nutrient removal yet.
Of 263 lagoon-named projects, six name ammonia or nitrogen. Six, out of 263.
The cheapest fix is often not a treatment fix.
Storage, a longer discharge window, land application and a water quality standards variance all change the problem without buying steel. Price those first.
02 · Reading the record
Before all five, check the clock. This is EPA’s Lagoon Inventory Dataset, published 2022, and its compliance columns are ECHO as of September 2021. Every exceedance figure on this page is a five-year-old lead, not a current fact, and EPA’s own documentation says to treat it that way. Live status for any one plant is two minutes away in ECHO and it is free.
An exceedance rate measures limits, not water
Nationally 12.7% of lagoons carry a filed ammonia exceedance. Michigan files 1.1%, and the reason is that 153 of its 177 lagoons sit on a general permit where ammonia is report-only. There is no limit to exceed. Michigan is not clean. Michigan is unmeasured.
Blank is not zero
Design flow is populated for 3,702 of 4,537 records. Michigan has one for 5 of its 177. Build a ranking on a mostly empty column and you rank the towns with tidy paperwork.
Some rows are not lagoons
This is built from facility records, not site visits. Detroit’s activated sludge plant sits in the Michigan lagoon subset. Before citing a named facility, pull its permit.
Absence proves nothing
Paw Paw, Pinckney and Kent City are confirmed operating Michigan lagoons and none of the three has a row. Private lagoons are excluded by design.
The population field is sometimes the whole city
EPA’s file carries a Houston lagoon at 0.3 MGD serving 2,310,432 people. That is 0.13 gallons per person per day. Of the rows with both fields, 11.6% come out under 10 gpcd, which is impossible, and those alone carry 9.9M of the 20.9M you get by naively summing the column.
The fifth one cost us a headline. An earlier draft of this page said lagoons serve about 21 million Americans. Keeping only the rows whose flow and population are mutually consistent gives 4.7 million, and that is the number above. The median never moved, because a median does not care about 410 wrong rows.
04 · The evidence
Every state publishes a Clean Water SRF project list each year. Who applied, for what, for how much. Read 39 of them together and you get the one thing no brochure will give you, which is what your peers actually spend money on.
That distribution is the most useful thing on this page. A lagoon town facing a nutrient limit gets told the answer is a capital project it cannot imagine affording. The lists say the typical funded lagoon project is a million and a half dollars, and the bottom quarter are half a million or less.
What the money is for
Projects can name more than one thing, so these do not sum to 100.
The same problem, three orders of magnitude apart. Unadilla, Nebraska listed a circulator in one cell to reduce ammonia, at $5,000. Green River, Wyoming listed a new plant to replace its lagoons entirely, for anticipated nutrient limits. Both are on a state funding list. Both are about ammonia. That is the range you are negotiating inside.
05 · The money
Clean Water SRF
You have to be on the list, but not at the top of it. Federal law lets a state fund a project only if it is on the priority list, and the same statute says assistance may be provided regardless of rank. Some of it you never pay back: states must put at least 10% of their capitalisation grant into principal forgiveness and may put in 30%.
USDA Rural Development
Built for exactly this population. Towns of 10,000 or fewer, loans up to 40 years, and a grant share set by your median household income: up to 75% if you are below the higher of the poverty line or 80% of your state’s nonmetro MHI, up to 45% between 80 and 100%, nothing above. Applications are rolling. There is no window to miss.
Start here if you have $0
Two USDA grants exist purely to pay for figuring out what to do. SEARCH covers up to 100% of predevelopment costs, capped at $30,000. Predevelopment Planning Grants cover 75%, capped at $60,000. Both rolling. That is a funded preliminary engineering report before you have committed to anything.
WIFIA now works for small towns
There is a track for communities of 25,000 or fewer that can finance up to 80% of project costs, and EPA has moved to waive its loan fees for them. WIFIA used to be a big-city instrument. Check whether that is still true before ruling it out.
The free help nobody claims
EPA’s Lagoon Action Plan produced a First Stop Toolbox, a troubleshooting manual and a national inventory, all free, and its window closes this year. Separately, EPA funds outside organisations to give small systems free direct technical assistance including help writing a funding application. It was renamed RealWaterTA in March 2026, so anything you read saying WaterTA is out of date.
The path that is not funding at all
If a limit is genuinely unaffordable, a water quality standards variance under 40 CFR 131.14 may be the answer. Your state adopts it, EPA approves it, and for its term it becomes the standard your permit is written from. Miss the five-year reevaluation and the variance is void, so put it in the calendar the day it is approved.
Three things people repeat that are wrong
The maximum CWSRF loan term is 30 years, not 40.
Federal law caps it at the lesser of 30 years or useful life. The 40-year extended term for disadvantaged communities is a drinking water provision and does not exist on the clean water side.
“Disadvantaged community” is the wrong phrase to use with your state.
On the clean water side the term is affordability criteria, and every state wrote its own. There is no national definition. Read your state’s Intended Use Plan for the one that governs you.
There is less money in FY2026 than FY2025.
Congress did not earmark directed community grants out of the SRF in FY2025 but did again in FY2026, so the funding available to states fell. A plan built on last year’s capacity is optimistic.
06 · Before you buy
Aimed at the supplier, the consulting engineer and the state, in that order. An operator on a Michigan committee agenda offered to give a talk called “How not to get conned by equipment suppliers.” That instinct is correct, and these are the questions underneath it.
What is my actual limit, in what months, and when does it change? Get the fact sheet, not the summary.
Am I on a general permit where nutrients are report-only? If so my compliance record proves nothing.
What do my own report-only numbers say? Many towns have sampled ammonia for years into a field with no limit attached and nobody has ever looked.
What does doing nothing cost? Price the enforcement, variance and schedule paths before pricing steel.
Have you shown me the option where I stop discharging? A company that sells treatment equipment will not raise it unprompted.
Three operating references at my design flow, in my climate. Then call the operators, not the sales engineer.
What does year eight look like? Media replacement, blower rebuilds, dredging interval, chemical cost, extra sludge.
What does this add to my power bill, and who did that math?
Can my current operator run it, at the certification they hold today?
Which funding source is this written for, and did the engineer use that program’s language? Ranking is competitive.
07 · Sources
The lagoon population.
EPA’s Lagoon Inventory Dataset, EPA-820-R-22-001, published 2022. 4,537 systems across 46 states. Compliance columns are ECHO as of September 2021 and EPA’s own documentation calls them leads to re-verify, not facts. Private lagoons are excluded by design; federal facilities are undercounted.
The spending picture.
5,677 wastewater projects read from 39 state Clean Water SRF intended use plans and priority lists. Vintage is mixed and mostly old: 16 of 38 dated sources are FY2025–27 and 23 are the 2022 or 2023 edition. A project counts as a lagoon project only when its own description says so, which undercounts. Dollar figures exclude Mississippi, North Dakota and Wyoming, whose lists report in units other than whole dollars.
What is deliberately not here.
No product names in the options section, no removal percentages, no payback periods, no cost per gallon, and no vendor claims dressed up as findings. Where a specific installation is described, a permit fact sheet, a state list or the town’s own record says so.
Disclosure.
The author advises a company in the algae-based nutrient recovery category described in section 3 and is exhibiting with it at WEFTEC 2026. No product, claim or figure from that company appears anywhere on this page. That is the reason for the constraint, not an accident of it.
Compiled by Mike German, Ph.D., P.E. · Steps Ventures · September 2026. Corrections are welcome and will be published. Tell me your state and I will cut it for you.