When commercial property managers think about utility cost optimization, the conversation almost always starts with electricity and natural gas. These are the largest line items on most operating statements, and they attract the bulk of attention during budget season. Water and sewer charges, by contrast, tend to get paid without scrutiny. They arrive, they get coded to the GL, and they disappear into operating expenses without anyone asking whether the amounts are correct.
That oversight is becoming increasingly expensive. Water rates across the United States have risen by an average of 4.5 percent annually over the past decade, outpacing inflation and, in many municipalities, outpacing electricity rate increases. Sewer charges, which are typically calculated as a multiple of water consumption, amplify the impact of every gallon that flows through the meter. For a portfolio of office buildings, retail centers, or multifamily properties, water and sewer costs can quietly climb into the hundreds of thousands of dollars per year without anyone on the operations team noticing the trend.
Why Water and Sewer Rates Are Accelerating
The fundamental driver behind rising water costs is infrastructure investment. Much of the nation's water and wastewater infrastructure was built in the mid-twentieth century and is now approaching the end of its useful life. The American Society of Civil Engineers has consistently rated the country's water infrastructure at a D or D-plus grade, estimating that trillions of dollars in capital investment are needed over the coming decades to replace aging pipes, treatment facilities, and distribution networks.
Municipalities fund these capital improvements primarily through rate increases. Unlike electricity, where competitive markets and fuel price fluctuations create some degree of rate volatility, water pricing is almost entirely a function of local government budgeting decisions. When a city decides to replace a water main or upgrade a treatment plant, ratepayers absorb the cost through higher volumetric charges, fixed fees, or both. There is no competitive alternative. You cannot shop for a different water provider the way you can procure electricity on the open market in deregulated states.
Several cities have implemented particularly aggressive rate schedules in recent years. Atlanta, for example, has seen water and sewer rates more than triple over the past fifteen years as the city invests in consent decree requirements. Philadelphia, Detroit, and parts of California have also implemented steep rate trajectories. Property managers operating in these markets who have not audited their water costs recently are almost certainly paying more than they realize.
The Sewer Ratio Problem
Sewer charges represent one of the most common sources of billing errors in commercial real estate, yet they are rarely examined during routine bill reviews. The fundamental issue is straightforward: sewer charges are typically calculated based on water consumption, under the assumption that water flowing into a building eventually flows out through the sewer system. Most municipalities bill sewer as a percentage of metered water usage, often at a ratio of 90 to 100 percent.
The problem is that this assumption is frequently wrong. Many commercial properties consume significant volumes of water that never enter the sewer system. Cooling towers evaporate water into the atmosphere. Irrigation systems distribute water across landscaping where it is absorbed by soil or evaporated. Manufacturing and food service operations may consume water in processes that do not discharge to the municipal sewer system. In each of these cases, the building owner is paying sewer charges on water that never reaches the sewer.
Applying for a Sewer Credit or Deduct Meter
Most municipalities offer mechanisms for commercial customers to reduce their sewer charges when they can demonstrate that a portion of their water consumption does not discharge to the sewer. The two most common approaches are sewer credits and deduct meters.
A sewer credit involves applying to the water authority with documentation showing that a specific percentage of water consumption is used for non-sewer purposes. If approved, the sewer charge is reduced by that percentage. A deduct meter is a physical meter installed on the water line feeding a specific non-sewer use, such as a cooling tower or irrigation system. The deduct meter measures the volume of water that bypasses the sewer, and that volume is subtracted from the sewer calculation each billing period.
The savings from sewer credits and deduct meters can be substantial. For a building with a 500-ton cooling tower operating during summer months, evaporative losses can account for 30 to 50 percent of total water consumption during peak cooling season. Removing that volume from the sewer calculation can reduce annual sewer charges by tens of thousands of dollars. The cost of installing a deduct meter is typically recovered within the first year of operation.
Leak Detection and Consumption Anomalies
Water leaks are a persistent problem in commercial buildings, and they are remarkably difficult to detect without systematic consumption monitoring. A toilet with a running flapper valve can waste 200 gallons per day. A small leak in an underground irrigation line can go unnoticed for months. A malfunctioning cooling tower float valve can allow thousands of gallons of continuous overflow. Each of these scenarios generates real charges on the water bill while delivering zero value to building operations.
The challenge with leak detection is that individual leaks are often too small to trigger an obvious spike in monthly consumption. A 200-gallon- per-day toilet leak adds roughly 6,000 gallons per month to a building that might consume 100,000 gallons in the same period. That 6 percent increase is easy to overlook on a single invoice. But multiplied across a portfolio of buildings operating over twelve months, these small leaks compound into material operating expenses.
Setting Up Consumption Baselines
Effective leak detection starts with establishing consumption baselines. A baseline represents the expected water consumption for a building during a given period, adjusted for occupancy, weather, and seasonal factors. When actual consumption exceeds the baseline by more than a defined threshold, the system flags the deviation for investigation.
The most effective baselines account for multiple variables. A building with cooling towers will naturally consume more water during summer months, so a flat annual baseline would generate false positives during cooling season and miss genuine anomalies during the winter. Similarly, a multifamily property with higher occupancy during certain months needs a baseline that reflects those occupancy patterns. Conduit automatically builds weather-normalized and occupancy-adjusted baselines for every meter in a portfolio, flagging deviations that warrant investigation while filtering out expected seasonal variation.
Audit Strategies for Water and Sewer Bills
A systematic water and sewer audit should cover several key areas beyond rate verification and sewer ratio review. The following checklist provides a framework for evaluating water and sewer costs across a commercial portfolio.
- Meter inventory verification: Confirm that every water meter associated with each property is accounted for in your records. It is not uncommon for properties to have meters that were installed for construction or temporary purposes and never decommissioned. These phantom meters generate minimum charges on every billing cycle.
- Rate class validation: Verify that each account is assigned to the correct rate class. Commercial properties occasionally end up on residential or small-commercial tariffs that carry different rate structures. In some cases, moving to the correct rate class results in lower per-unit charges.
- Sewer ratio review: Determine whether your buildings have cooling towers, irrigation systems, or other water uses that do not discharge to the sewer. If so, investigate sewer credit programs or deduct meter installations with the local water authority.
- Consumption trend analysis: Plot monthly water consumption for each meter over at least 24 months. Look for unexplained increases, flat-line patterns that suggest estimated reads, and seasonal patterns that do not align with building operations.
- Billing period overlap: Check for overlapping or duplicate billing periods. Water utilities occasionally issue corrected bills without properly crediting the original, resulting in double charges for the same consumption period.
- Stormwater fee review: Many municipalities charge stormwater fees based on impervious surface area. If your property has installed retention ponds, green infrastructure, or permeable surfaces, you may qualify for stormwater fee reductions.
The Financial Impact of Water Cost Optimization
The aggregate impact of water and sewer cost optimization is often larger than property teams expect. Consider a portfolio of twenty commercial buildings with an average annual water and sewer spend of $40,000 per building. That represents $800,000 in annual water and sewer costs across the portfolio. A systematic audit that identifies sewer ratio corrections, eliminates leak-driven waste, and removes phantom meters can typically reduce water and sewer costs by 10 to 25 percent.
At the conservative end of that range, a 10 percent reduction saves $80,000 per year. At the aggressive end, a 25 percent reduction saves $200,000. These savings drop directly to NOI, which means they also enhance property value. At a 6 percent cap rate, $80,000 in annual savings translates to more than $1.3 million in incremental property value across the portfolio. At $200,000 in savings, the value impact exceeds $3.3 million.
Water and sewer costs are the last major utility category where most commercial portfolios have done little to no optimization work. The savings are real, the payback periods are short, and the audit process is straightforward once you have clean data.
Getting Started with Water and Sewer Optimization
The first step in any water and sewer optimization effort is centralizing your data. Most property management teams track electricity and gas consumption in their energy management systems but leave water and sewer bills in accounts payable systems where they are difficult to analyze. Bringing water data into a unified utility management platform allows you to run the consumption analyses, baseline comparisons, and billing audits described above.
Conduit ingests water and sewer bills alongside electricity, gas, and other utility commodities, normalizing the data into a consistent format that supports portfolio-wide analysis. The platform automatically flags consumption anomalies, identifies potential sewer credit opportunities, and tracks rate changes over time so that your team can focus on investigating and resolving issues rather than manually compiling spreadsheets.
For property teams that have never conducted a water and sewer audit, the opportunity is significant. Start with your highest-consumption buildings, focus on sewer ratio corrections and leak detection, and expand the program across the portfolio as you demonstrate results. The data will pay for itself.