Picture this: you close on a 90-lot mobile home park. The numbers look strong. NOI supports the price. You’ve done your due diligence — or so you think.

Then the first water bill arrives.

$9,200. For one month. And your residents? They pay nothing.

Welcome to the master-metered park trap — and it’s one of the most expensive surprises in mobile home park investing.

What “Master Metered” Actually Means

In a master-metered park, the owner pays a single consolidated water and sewer bill from the municipality (or manages a private well and wastewater system). Residents pay one flat lot rent amount that may or may not include utilities — but they have no separate meter and no direct accountability for how much water they use.

The parks most likely to be master-metered are those built before 1980, when this was the standard construction model. Sellers of these parks often understate utility expenses in their pro formas — or normalize them so that they appear manageable — making them look more attractive than they are.

In reality, being master-metered means you’re effectively providing unlimited free water to all of your residents. The consequences are predictable: consumption is 20–40% higher than in individually-metered parks, and you bear 100% of the cost.

The Math Is Brutal

A 100-lot park in the Southeast might pay $6,000–$10,000 per month for water and sewer. That’s $72,000–$120,000 per year coming straight out of NOI. At a 7% cap rate, that’s $1.0M–$1.7M of value destroyed that could be recovered by passing through utility costs to residents.

This is not a rounding error. For many park owners, it’s the difference between a strong return and a mediocre one.

The Three Paths to Recovery

Option 1: Individual Submetering

The gold standard. Install individual water meters on each lot, read them monthly, and bill residents for actual usage. Once implemented, residents reduce consumption by 20–30% almost immediately — a behavioral economics phenomenon called the “metered-water effect.” You stop subsidizing waste.

The cost? Typically $800–$3,000 per lot for equipment and installation, depending on your park’s infrastructure age and local permit requirements. For a 100-lot park, you’re looking at $80,000–$300,000 in capital investment.

ROI timeline: 18–36 months in most markets, depending on how much water you were eating and what residents will reasonably pay. After break-even, it’s pure NOI improvement.

Key: use an Automatic Meter Reading (AMR) system rather than manual reads. AMR systems transmit usage data automatically, catch leaks in real time, and dramatically reduce billing labor. Companies like Metron-Farnier and Mueller Water Products specialize in this for manufactured housing communities.

Option 2: RUBS — Ratio Utility Billing System

If submetering capital is out of reach, RUBS is your interim solution. Instead of installing individual meters, you allocate the master water bill to residents based on a ratio — typically square footage of the home, number of occupants, or a flat per-lot split.

RUBS is legal in most states, but here’s the trap: the rules vary dramatically by jurisdiction, and getting them wrong creates real legal exposure.

At minimum, a proper RUBS implementation requires:

• A lease addendum that explicitly authorizes utility pass-through billing
• Written notice to residents with a defined lead time (30–90 days, depending on your state)
• A documented and consistent calculation methodology
• Monthly billing statements that show the allocation formula
• Compliance with any state-specific caps on pass-through amounts

States like California and Illinois have additional requirements. Other states are permissive. Before you implement RUBS, spend $1,500–$3,000 with an attorney familiar with manufactured housing law in your state. It’s cheap insurance.

Option 3: Address Private System Risk Before It Becomes a Crisis

If your park is on a private well and/or lagoon wastewater system, you’re operating in a different risk category entirely.

EPA enforcement on private wastewater systems — particularly lagoons — has escalated significantly. Parks with aging lagoons are receiving notices, consent orders, and fines. Connection to municipal sewer, when required, can cost $500,000–$2,000,000 or more depending on distance and terrain.

Don’t wait for the notice to arrive. Get an environmental assessment on any private system within the first 90 days of ownership. Know your risk. And explore USDA Rural Development grants and loans — the Water & Waste Disposal Loan & Grant program exists specifically to help rural communities (including MHPs) fund infrastructure upgrades, and many operators don’t know it exists.

The Hidden Upside: Leak Detection

One underappreciated benefit of submetering: you see leaks. In a master-metered park, a broken line under a lot can run for months before anyone notices, burning through thousands of dollars of water. With individual meters, a spike in usage on Lot 47 is an immediate flag. You catch it, you fix it, you stop the bleeding.

At Keel Team, we’ve had individual lot meters catch leaks that would have cost us $15,000–$30,000 in water bills before the old system would have detected them.

What to Do at Acquisition

If you’re evaluating a master-metered park, here’s your due diligence checklist:

1. Get 24 months of actual utility bills. Not seller estimates. Actual bills. Line them up monthly.
2. Calculate your true utility cost per occupied lot. Anything over $50–$60/lot/month is a red flag.
3. Research your state’s RUBS and submetering laws before you close. Know what you’re walking into.
4. Budget for submetering in your CapEx plan. Price it out, include it in your projections, and factor it into your offer.
5. Inspect water mains. Ask the seller when the mains were last replaced. Get a camera inspection on older systems.

For a complete due diligence system that covers utilities, infrastructure, and dozens of other acquisition risk factors, check out our MHP Due Diligence Playbook at keelteam.com/mhp-due-diligence-playbook. The utility section alone has saved operators from six-figure surprises.

The Bottom Line

The master-metered park isn’t necessarily a deal-killer — but it is a deal-changer. The operator who buys it without a plan is paying for everyone’s showers and leaving massive value on the table. The operator who executes a submetering or RUBS conversion in Year 1 is unlocking a six-figure NOI improvement that wasn’t in the acquisition pro forma.

At Keel Team, we’ve navigated utility conversions in dozens of parks. The process is manageable. The returns are real. And the downside of doing nothing — writing $100,000+ water checks every year — is the most preventable expense in this business.