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The case for water

The Water Conservation Market Is Bigger Than It Looks

Why building age, fixture-era vintage, and a decade of rate escalation make water the most underused lever in the ESCO project, and how to capture it without leaving other ECMs behind.

1. The buildings ESCOs serve are old, and that's the point

ESCO industry revenue is concentrated almost entirely in one part of the building stock: public and institutional customers (federal, state, and local government; colleges and universities; and K-12 school districts) accounted for over 90% of U.S. ESCO industry revenue in 2018, a share consistent across multiple LBNL industry studies going back years. That happens to be exactly the segment of the building stock with the oldest average age in the country:

• K-12 schools: the average main instructional building in a U.S. public school is 49 years old, per the National Center for Education Statistics' most recent facilities survey (Dec. 2023); 38% of main instructional buildings were built before 1970.
• Higher education: Gordian's facilities database, covering more than 50,000 campus buildings across roughly 300 institutions, put the average campus building age at "approaching 50 years" in its 2021 joint report with APPA, with $112 billion in urgent deferred renewal identified nationally.
• Government buildings: GSA, the federal government's largest landlord, has repeatedly reported an average building age of 46 years across its owned real property portfolio, with over 500 buildings built before 1950; a separate GSA study of its own high-performance building stock put the average at just over 60 years.

The takeaway for anyone scoping an ESCO project: the customer base ESCOs are built to serve is, on average, the oldest building stock in the country, and the plumbing fixtures inside those buildings have had 40 to 50+ years, and at least one full water-efficiency mandate cycle, to drift, degrade, or simply never get upgraded past whatever was code-minimum when they were last touched.

2. 1994–2005: the prime-target fixture vintage

Layered on top of an old building stock is an even more specific problem: a large share of the plumbing fixtures actually installed in that stock date to one narrow, well-documented window. EPAct '92 forced a nationwide fixture changeover starting January 1, 1994, and a wave of renovations, remodels, and code-driven replacements through the mid-2000s put exactly the first, worst-performing generation of low-flow fixtures into buildings that, per Section 1, are otherwise still in service today, largely unrenovated since.

• Tank toilets: as covered in our companion research on tank-toilet drift, 1994–2003-era 1.6-gpf fixtures commonly hit that number by fitting a legacy 3.5–5.5+ gpf tank with an early-close flapper or displacement baffle rather than a redesigned tank and trapway. NAHB Research Center testing found flush volumes as high as 2.91 gpf after a generic (non-original) flapper replacement, and the Koeller field study of 852 in-service fixtures found a mean flush volume of 1.76 gpf, already above the 1.6-gpf nameplate before any catastrophic part failure.
• Flushometer toilets: the commercial-fixture equivalent of the same era's problem, with a twist. A 1994–2003-era flushometer valve wasn't necessarily throttled down with a retrofit trim like a tank toilet; it was frequently paired with a bowl and trapway that, as documented in our companion research on design-standard retrofits, simply weren't redesigned for the lower volume, so a fixture flushing exactly 1.6 gpf as intended still double-flushed routinely because the bowl and trapway couldn't clear waste in one pass. Facility staff fixing that complaint often had a much easier fix available at the valve than at the bowl: Sloan and other manufacturers sell 3.5-gpf diaphragm rebuild kits that install in the identical Regal/Royal-style valve body as the 1.6-gpf kit, and a diaphragm has only a 4–6-year service life before it needs replacing anyway. A maintenance tech solving a double-flushing complaint with the parts on the truck, or a plumber simply grabbing a higher-flow kit that's known to work, can quietly convert a code-compliant 1.6-gpf valve back to 3.5 gpf with a five-minute repair and no record that a water-saving fixture was ever there. Either failure mode (a valve reverted to a high-flow kit, or a valve left at 1.6 gpf but chronically double-flushed by its bowl and trapway) produces the same result: a fixture that looks efficient on the as-built drawings and isn't in practice.
• Urinals: pint-flush (0.125 gpf) urinals did not exist as a market category until roughly 2010 (Los Angeles' 2010 mandate) and were not broadly codified until California's Title 24 flush requirement took effect in 2016. Every urinal installed from 1994 through that window was built to the EPAct '92 federal ceiling of 1.0 gpf, eight times the flush volume of a current 0.125-gpf high-efficiency urinal, and EPA's own WaterSense program estimates that as many as 65% of the roughly 12 million urinals in service in the U.S. exceed even that 1.0-gpf federal minimum. In other words: in most buildings built or last plumbed in this window, there is no 0.5-gpf or 0.125-gpf urinal hiding in the fixture count to find. The entire population is a full order of magnitude away from current best practice, whether or not it's functioning exactly as designed.
• Faucets: a 0.5-gpm public lavatory aerator specified and installed during an original EPAct-era retrofit or a later water-utility rebate program has no guarantee of staying at 0.5 gpm. Maintenance staff replacing a worn aerator during routine repair, or a general contractor swapping fixtures during an unrelated remodel, commonly reaches for whatever aerator is in stock, frequently a generic 2.0-gpm part with no low-flow rating at all, silently erasing 75% of the intended savings with no record of the change and no visible sign at the fixture. This is the same failure mode documented in our companion research on mismatched diaphragm kits in flushometer valves: the part gets swapped, the nameplate or spec sheet doesn't, and nobody finds out until someone measures it.

3. Water and sewer rates have made the other side of the math much bigger

Even a fixture performing exactly as designed in 1998 is now saving money against a completely different rate environment. Nationally, water, sewer, and trash collection prices rose 207% between January 2000 and December 2025, versus 93% for overall consumer inflation over the same period, per Bluefield Research's 50-city Municipal Water & Sewer Rate Index, with rates rising another 5.1% in 2025 alone, outpacing inflation yet again. Circle of Blue's 30-city survey separately found a 41% increase in average residential water prices just from 2010 to 2015, and LBNL's own analysis of BLS consumer price data identifies an inflection point around 2002–2003 after which water and sewer CPI began climbing measurably faster than the general CPI, right in the middle of the fixture-vintage window in Section 2.

That national trend is driven in real markets by a specific and recurring pressure: federal Clean Water Act enforcement against aging combined and sanitary sewer systems. Atlanta is the clearest example. Under EPA/DOJ consent decrees dating to 1998 and 1999, the city has spent more than $4 billion on sewer separation, storage tunnels, and treatment upgrades, and as Atlanta's own mayor acknowledged in 2012, water and sewer rates in the city had more than tripled since 2003 to fund that compliance work: a direct, traceable line from a federal mandate to a rate increase, not a generic inflation story. Baltimore, Cleveland, and dozens of other older sewer systems are under similar decrees today, which means the same math is playing out, at different stages, in many of the cities where ESCO customers operate.

4. Why the market is bigger than it looks on paper

Put Sections 1–3 together and the size of the opportunity stops being a simple "swap 1.6 gpf for 1.28 gpf" calculation. Three separate multipliers are stacking in the same direction: the buildings are old, the fixtures inside them are disproportionately drawn from the worst-performing vintage the market ever produced, and the price of every gallon not saved has risen two to three times faster than inflation since those fixtures went in. None of that shows up by reading a fixture's nameplate. A 1.6-gpf stamp on a toilet installed in 1998 tells an engineer nothing about whether it's currently delivering 1.6 gpf, 1.76 gpf on average, or spiking to 2.91 gpf on a worn flapper; a 1.0-gpf urinal from the same era isn't a code violation anywhere, but it's still using eight times the water of the 0.125-gpf fixture that code allows today. The result is a water conservation opportunity that's systematically invisible to a scope built only from stamped flush volumes and as-built drawings, which is exactly why it tends to get underestimated by engineers pricing a project from paper rather than from a field audit.

That also means the fix isn't uniform. Some of this opportunity is recommissioning: restoring an already-compliant-looking fixture to the flush or flow volume it was designed and originally installed to hit, where the part has drifted or been mismatched over time. Some of it is wholesale replacement: a fixture that is functioning exactly as designed and still using multiples of what's achievable today, where no amount of recommissioning closes the gap. Treating every old fixture as a simple swap, and assuming every 1.6-gpf-stamped toilet is already "done," both under-scope the real opportunity in different ways.

5. Water's payback and what it buys the rest of the project

Against today's rate environment, a well-scoped water ECM is now routinely one of the shortest-payback measures available in a comprehensive ESPC. A 126-fixture flushometer recommissioning project we've documented elsewhere delivered a 1.4-year payback and a 15% building-wide water use reduction on a $32,000 scope. That kind of payback isn't just good on its own; it changes what the rest of the contract can afford to include. DOE's Federal Energy Management Program explicitly recommends bundling water efficiency measures into a performance contract for exactly this reason: a short-payback water ECM helps carry longer-payback measures that couldn't qualify for the contract on their own. Federal ESPC rules formalize the same logic. A measure that wouldn't independently pay back within twenty-five years is only permissible if the contract as a whole meets that payback threshold, which means every dollar of fast water payback directly expands how much slower-payback envelope, controls, or mechanical work can be bundled into the same guarantee.

Leaving water off the table, in other words, isn't a neutral scoping decision. It removes some of the best cash flow available to the contract and can shrink how much of the rest of the building's deferred-maintenance backlog (the same backlog documented in Section 1) the project can actually afford to address.

6. The case for an experienced water conservation contractor

Capturing this opportunity requires treating water the way a good energy engineer already treats lighting or HVAC: with a field audit that measures actual delivered flush and flow volumes, not a desk review of nameplate ratings and installation dates. That audit is what tells a project team whether a given fixture needs recommissioning, replacement, or nothing at all, and it's what makes the resulting savings measurable and verifiable rather than assumed, the same standard already expected of every other ECM in a guaranteed savings contract. An experienced water conservation contractor brings that combination: the field diagnostic skill to find where a building's fixtures have actually drifted from their nameplate, the design judgment to know when recommissioning is enough and when full replacement is the only real fix, and the measurement and verification discipline to prove the water savings on paper are the water savings the meter shows, while leaving the building's plumbing system performing as well as, or better than, it did the day the project closed.

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