How Reducing Water Waste in Multifamily Properties Impacts NOI

By SemperScreen®. We own residential and commercial real estate properties across the United States, and we built the permanent sink screen for our own buildings before we sold it to anyone else.

Four levers lower a multifamily water bill: fix leaks, replace fixtures, bill water by unit, and remove equipment that uses water without doing a fixture's job. Utility rebates carry most of the first two. The last one is the garbage disposal, which draws no water itself but runs the tap every time it is used.¹ Every dollar off the bill is a dollar of net operating income. Plus, some states now require water efficiency in new residential and non-residential construction such as with the 2025 California Green Building Standards Code (CALGreen), found in Title 24, Part 11 of the California Code of Regulations.¹³

Which levers actually lower a multifamily water bill?

In the order we work them on our own buildings:

1. Leaks. A running toilet or a dripping supply line costs money every hour, and fixing it needs no sign-off from anyone. This is always first.
2. Fixtures. Toilets, urinals, aerators and flow control valves. Slow, capital-heavy, and the place where rebate money actually sits.
3. Billing. Submetering or ratio billing moves the cost to the resident who creates it. It changes who pays before it changes how much is used.
4. Equipment that uses water without doing a fixture's job. In a unit kitchen, that is the garbage disposal. It is the only item on this list you can remove outright rather than replace.

The first two usually move more gallons. The fourth is the one that also removes a maintenance line, which is why it earns its own section below.

Does billing residents for water actually lower usage?

When water is included in the rent, the resident gets no signal either way. Billing changes that in one of two ways. Submeters measure the unit and bill what it used. A ratio utility billing system, or RUBS, skips the meters and allocates the building's master bill by formula, usually some mix of square footage, bedrooms and bathrooms, occupancy and fixture count.² The formula is an estimate rather than a measurement.³

That distinction decides whether conservation follows. A housing management training body's own comparison rates submetering as exact, with high tenant acceptance and a high conservation incentive, and rates RUBS as estimated with a low one, because a RUBS bill tracks the building's total and the formula rather than what a resident did that month.² Owners still pick RUBS because it needs no meters and no capital work.³ Cost recovery lifts net operating income either way, which is the manager-side benefit that body lists first.²

Where the rules are written down, the setup is specific. In Massachusetts an owner who bills occupants separately for water has to install a submeter that measures only that unit, put ultra-low-flush toilets and conservation devices on the showers and faucets, put the arrangement in a written rental agreement, and file a certificate signed by a licensed plumber.⁴

The method carries jurisdiction risk worth checking before you plan around it. In Los Angeles, the city housing department has recommended banning RUBS in rent-stabilized units, a step West Hollywood and Oakland have already taken, and landlords there are not required to disclose how the fees are calculated. The state attorney general settled a case last October over allegations that RUBS charges alongside a rent increase violated California's Tenant Protection Act. Landlord associations oppose a ban and argue the practice encourages conservation, which tenant advocates dispute.⁵

Billing decides who pays and, with meters, gives the resident a real signal. It does not take an appliance out of the kitchen, and it does not stop a clog.

Are there rebates for lowering water bills in multifamily properties?

Yes, and the terms belong to your own water provider rather than to any national program. Two rules travel well. Commercial customers and owners of multifamily buildings of five units or more generally have to get a rebate reservation approved before buying anything, with a fixed window to purchase and install afterward.⁶ And funding runs out, so approval is first come, first served.⁶

What the device lists cover is narrow: premium high-efficiency toilets, ultra low-flow and zero water urinals, plumbing flow control valves, irrigation hardware, and food service equipment.⁷ A screen in a sink drain is not on those lists, and we would rather say so than imply otherwise.

Two programs sit outside the device lists and are worth a call before any work is scheduled:

• Pay-for-performance. Some providers run an incentive for non-residential customers improving water efficiency through equipment or services that do not qualify for standard rebates, paid on the amount of water actually saved.⁷
• The sewer side of the bill. Wastewater agencies often estimate your discharge from standard factors rather than metering it. The Los Angeles County Sanitation Districts run a Low-Water Rebate Program for exactly that reason, letting low-water users apply for a reduced service charge when actual discharge is well below the estimate.⁸

Removing disposals across a portfolio is a measurable change in water use, which makes it a fair question to put to your provider under either heading. Ask before the work starts, because pre-approval is the rule almost everywhere.

How much water does a garbage disposal use?

A garbage disposal draws no water on its own. EPA's WaterSense at Work guidance for commercial kitchens puts conventional food disposal equipment at a constant freshwater flow of 1 to 10 gallons per minute while in use, and food disposers specifically at 3 to 10 gallons per minute.¹ Timers and load sensors reduce or shut off that flow while the equipment sits idle, and EPA notes that the disposal's water use can be eliminated by collecting food waste with a "food strainer" in the bottom of the sink instead.¹ The Department of Energy lists food disposals among the water-using pieces of commercial kitchen equipment, beside ice makers, dishwashers and pre-rinse spray valves.⁹ Under the LEED® green building program, LEED v5 (WEc2 Enhanced Water Efficiency, Option 3, Table 4) rates a food waste disposer at 3–8 gpm under full load and a "strainer basket" at no additional water usage.¹⁴ The SemperScreen® permanent sink screen contributes toward satisfying credit Enhanced Water Efficiency under LEED®.

Those figures come from commercial kitchens. In a unit kitchen the arithmetic is simpler, and you already have every number it needs:

• Tap run time per use: the common 30-second rule runs water for 30 seconds before and 30 seconds after each grind¹⁵
• Uses per day per unit, from your own experience of the property
• Units with a disposal installed
• Your water and sewer rate, which varies far more between cities than usage does

Multiply those four against your own utility bill rather than a published average. A number you built from your own rate survives a conversation with an asset manager. A number from someone's blog does not.

Is the disposal allowed, though?

It is, and the honest version of this argument has to start there. Federal efficiency guidance does not tell facilities to rip disposals out. It tells them to meter the water: fit a load sensor, add a timer that shuts the flow off, run cold water rather than hot.¹ Housing code takes the same posture, listing garbage grinders as permitted equipment that an owner may choose to install and then has to maintain.⁴

So the case here is not that a disposal is disallowed. It is that a disposal is an appliance you pay for twice, in water while it runs and in service calls after it runs, and a screen in the same drain has no water connection and no motor at all. One of those two numbers can be taken to zero by removing a part. The other cannot.

Is the disposal required in a rental unit?

Requirements vary by jurisdiction, so check yours before anything is scheduled. Massachusetts is a useful example because its habitability code is explicit. The owner must provide a kitchen sink of sufficient size and capacity for washing dishes and kitchen utensils, while garbage grinders appear on the code's list of owner-installed optional equipment, alongside dishwashers and air conditioners.⁴ The sink is the requirement. The grinder is an option you are maintaining.

The same code sets the timing: an owner may remove owner-installed optional equipment when a unit has been vacated or before a new tenancy.⁴ That is turnover, which is also when the unit is empty enough to do the work. For the habitability question in more detail, see can a landlord remove a garbage disposal from a rental.

What does the disposal send into the drain line?

Grinding changes the size of the food. It leaves the same material in the pipe, in smaller pieces. The Tahoe City Public Utility District reports that two-thirds of sewer backups happen in the homeowner's own sewer line, frequently caused by things flushed down the toilet or ground up in the garbage disposal.¹⁰ Grease compounds it: EPA's report to Congress found grease from restaurants, homes and industrial sources caused 47 percent of reported blockages.¹¹

In a building, that arrives as a work order. Drain and plumbing clogs are one of the top three maintenance ticket categories, at $250+ per call, and the same drains tend to produce them. Our list of the foods that cause clogged drains covers what is actually going down there.

How does this show up in NOI?

Reducing water waste in multifamily properties lowers operating expenses, and every dollar of operating expense removed is a dollar of net operating income. The disposal touches two lines at once: the water it uses, which is small per unit and constant across the portfolio, and the clog tickets it feeds, which are larger per event and unpredictable. Leaks and fixtures move the first line further. Neither of them touches the second.

The fix also has to survive the tenant. NIOSH rates engineering controls as more effective than administrative controls such as training, because engineering controls work without significant human interaction.¹² A line in the move-in packet is an administrative control. A drain that will not pass food is an engineering one, and clogs come from human error that no training program fixes.

Run the portfolio numbers on your own rate and your own ticket history, then read why owners are eliminating garbage disposals for the decision itself.

"We installed a SemperScreen® sink screens in each of our units. Our tenants love saving money on water and I love not having to worry about broken garbage disposals or clogged drains anymore."

Bernardo, Resident Property Manager

What goes in the drain when the disposal comes out?

The opening left behind is a standard kitchen sink drain, and something has to occupy it. The SemperScreen® permanent sink screen is the only non-removable permanent sink screen. It fits standard 3½" drains and stops food waste down to the size of a dry grain of rice (screen aperture 0.08 in / 2.0 mm maximum), ensuring most food waste that can harm a drain stays out of the drain. Cleaning is one step. Just scoop it out!

It is polished stainless (304 stainless steel), installs in ~15 minutes per drain, retrofit, no plumbing modifications, and was tested and COMPLIED with ASME A112.18.2-2020 / CSA B125.2-20. The test reports are on our site. SemperScreen® recommends that you always refer to local building codes when modifying a building's plumbing system.

If the disposal is coming out this turn, how to change a garbage disposal to a regular drain walks through the plumbing.

Shop SemperScreen® →

For rental and property teams: We know you have at least one drain that keeps clogging (we have experience with those). Contact us and let's discuss testing our permanent sink screens in those bad drains.

Commercial properties (restaurants, hotels, retail breakrooms, hospitals, senior care facilities, office breakrooms, industrial warehouses) have some of the same issues with food waste. Find out what we recommend in these larger facilities, or model your own numbers with the drain protection ROI calculator.

Frequently asked questions

What are the most important ways to lower water bills in multifamily properties?
Fix leaks first, because they cost the most and need no approval. Then fixtures, then unit-level billing, then equipment that uses water without doing a fixture's job. Utility rebates carry most of the fixture work, and reservations usually have to be approved before anything is bought.⁶

Are there rebates for lowering water bills in multifamily properties?
Yes, and they are set by your own water provider. Device lists run to toilets, urinals, flow control valves and food service equipment.⁷ Equipment outside those lists can sometimes go through a pay-for-performance program that pays on measured savings instead.⁷

Do garbage disposals use a lot of water?
The disposal draws none by itself. What uses water is the tap running while it grinds, which EPA's guidance for commercial kitchens puts at 1 to 10 gallons per minute for food disposal equipment, and 3 to 10 for disposers.¹ In a unit kitchen it is a shorter run, repeated in every unit every day.

Can a landlord remove a garbage disposal?
Requirements vary by jurisdiction. In Massachusetts the kitchen sink is required and garbage grinders sit on the list of owner-installed optional equipment, which an owner may remove once a unit has been vacated or before a new tenancy.⁴

Does a permanent sink screen use water or electricity?
No. It has no motor and no water connection, so there is nothing to run and nothing to switch on. Food stays in the screen until someone scoops it into the trash or the compost bin.

References

1. U.S. Environmental Protection Agency, WaterSense. "WaterSense at Work: Commercial Kitchen Equipment, 4.9 Food Disposal Equipment." EPA 832-F-23-003, Office of Water. February 2025. Retrieved from https://www.epa.gov/system/files/documents/2023-05/ws-commercial-watersense-at-work_Section_4.9_Food_Disposals.pdf
2. National Center for Housing Management. "RUBS: Ratio Utility Billing System Explained for 2026." July 31, 2026. Retrieved from https://www.nchm.org/rubs-ratio-utility-billing-system-explained/
3. Commercial Real Estate Finance Company of America. "RUBS System for Multifamily Properties." Knowledge Center. Retrieved from https://www.crefcoa.com/ratio-utility-billing-system.html
4. Massachusetts Department of Public Health. "105 CMR 410.000: Minimum Standards of Fitness for Human Habitation (State Sanitary Code, Chapter II)," §§ 410.003(D), 410.100(A)(3), 410.130(C), 410.235(B)(3). Mass. Register #1498, June 23, 2023. Retrieved from https://www.mass.gov/doc/105-cmr-410-minimum-standards-of-fitness-for-human-habitation-state-sanitary-code-chapter-ii/download
5. Tso, Phoenix. "Their utility bills skyrocketed, so they stopped paying them." LA Public Press, July 20, 2026. Retrieved from https://lapublicpress.org/2026/07/la-renter-utilities-eviction-rubs-city-council/
6. Los Angeles Department of Water and Power. "Commercial Water Rebates (SoCal Water$mart)." Retrieved from https://www.ladwp.com/cwr
7. City of Riverside Public Utilities. "Water Rebates: Commercial Programs and the Water Savings Incentive Program." Retrieved from https://riversideca.gov/utilities/businesses/rebates/water-rebates
8. Los Angeles County Sanitation Districts. "Low-Water Rebate Program." Wastewater Revenue Program. Retrieved from https://www.lacsd.org/services/wastewater-programs-permits/wastewater-revenue-program/low-water-rebate-program
9. U.S. Department of Energy, Federal Energy Management Program. "Best Management Practice #11: Commercial Kitchen Equipment." Retrieved from https://www.energy.gov/eere/femp/best-management-practice-11-commercial-kitchen-equipment
10. Tahoe City Public Utility District. "What Not To Put Down Your Toilet or Drains: Frequently Asked Questions." February 19, 2015. Retrieved from https://www.tcpud.org/sites/default/files/documents/ffres.pdf
11. U.S. Environmental Protection Agency, Office of Water. "National Pretreatment Program (40 CFR 403): Controlling Fats, Oils, and Grease Discharges from Food Service Establishments." EPA-833-F-12-003. September 2012. Retrieved from https://www.epa.gov/system/files/documents/2021-07/pretreatment_foodservice_fs.pdf
12. National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. "Hierarchy of Controls." Updated April 10, 2024. Retrieved from https://www.cdc.gov/niosh/hierarchy-of-controls/about/index.html
13. "Division 4.3-Water Efficiency and Conservation" & "Division 5.3-Water Efficiency and Conservation". 2025 California Green Building Standards Code (CALGreen), found in Title 24, Part 11 of the California Code of Regulations. Retrieved from https://codes.iccsafe.org/content/CAGBC2025P3/chapter-4-residential-mandatory-measures#CAGBC2025P3_Ch04_SubCh4.3
14. U.S. Green Building Council. "LEED BD+C: New Construction v5, WEc2 Enhanced Water Efficiency," Option 3, Table 4. Retrieved from https://www.usgbc.org/credits/new-construction/v5/wec2
15. House Digest. "What Is The 30-Second Rule For Garbage Disposals?" Retrieved from https://www.housedigest.com/2259691/what-is-the-30-second-rule-for-garbage-disposals/