Every year, mobile home park investors lose hundreds of thousands of dollars not because they picked the wrong market or overpaid on cap rate — but because they didn’t know what was buried underground.

The #1 killer of mobile home park deals isn’t cap rate compression. It’s the infrastructure you can’t see until it’s already your problem.

Here’s what’s actually happening out there, and what you need to do before you sign anything.

What “Aging Infrastructure” Actually Means

When people say mobile home parks have “aging infrastructure,” they’re not talking about peeling paint or dated landscaping. They’re talking about:

• Orangeburg sewer lines — a tar-paper and pitch composite pipe used widely from the 1930s through the 1970s. It works until it doesn’t. Then it collapses. Replacement cost: $40,000+ per lot if it’s widespread.
• Galvanized water lines — corrode from the inside out over 40–50 years. Symptoms: brown water, low pressure, sky-high water bills you’ll inherit the moment you close.
• Private wastewater treatment systems — lagoons, septic fields, and small treatment plants that require EPA compliance. One violation: $10,000 per day in fines. An aging system that needs replacement: easily $500,000–$2,000,000.
• Undersized or improperly installed electrical infrastructure — the utility company engineer tells you post-close that the system needs a full upgrade before you can bring in new homes. Surprise: six figures you didn’t model.

Parks built between 1950 and 1975 have all of this sitting underground, and most sellers won’t volunteer the information.

The Due Diligence Mistakes That Keep Burning Investors

After reviewing post-mortems on deals that went sideways, these are the mistakes that come up over and over:

1. Only Reviewing 3 Months of Utility Bills

Sellers will give you whatever period makes the park look best. You need a minimum of 12 months — ideally 24–36 — to see seasonal patterns, leak events, and whether the seller was absorbing costs they plan to stop absorbing the moment you take over. Request the actual utility company bills, not owner-generated summaries. There’s a difference.

2. Skipping the Sewer Camera Inspection

A general property inspector won’t tell you the condition of your sewer lines. You need a licensed plumber to run a camera through the main lines and any laterals they can access. Cost: $500–$1,500. The cost of finding out post-close that you need 80 lots re-lined: $200,000+. This is not optional. This is a deal-or-no-deal line item.

3. Not Calling the Utility Company Engineer

Before you close on a park, call the power company’s engineer who services that grid. Ask them directly: “Are there any planned system upgrades? Any known issues? If I add 10 homes to this park over the next 3 years, what will I need to upgrade?” You’ll be surprised what they’ll tell you — and surprised that no one told you before.

4. Getting a Boundary Survey Instead of an ALTA

A boundary survey tells you where the property lines are. An ALTA survey tells you where everything is relative to those lines — including whether any mobile homes are actually sitting outside the property line. We’ve seen deals where 3–4 homes were encroaching on adjacent property. The cost to fix that — legally, financially, logistically — is not small.

5. Ignoring Environmental Red Flags

If the park has an old gas station on site, underground storage tanks, or a dry cleaner adjacent — get a Phase I environmental assessment. Full stop. Environmental remediation costs can be in the millions and can render a property nearly unsellable.

How We Approach Infrastructure Due Diligence at Keel Team

We’ve looked at hundreds of mobile home parks across the Southeast. Here’s the non-negotiable framework we use before submitting any serious offer — and the same framework we’ve documented in detail in our Mobile Home Park Due Diligence Playbook.

Pre-LOI Triage (before spending any due diligence money):

• Confirm public city water and city sewer (private systems require 2x scrutiny minimum)
• Request 24 months of utility bills and look for any usage anomalies
• Ask the seller directly: any infrastructure work done in the last 5 years? Any deferred maintenance?
• Check EPA violation history (public record)

Post-LOI Due Diligence:

• Hire a plumber for sewer camera inspection — every main line
• Hire an electrician to inspect electrical infrastructure and speak with the utility company engineer
• Review all water and sewer bills for the full ownership period if possible
• ALTA survey — not a boundary survey
• Phase I environmental if there are any red flags
• Get CapEx estimates from local contractors for any known issues

The math: Spending $5,000–$8,000 on thorough infrastructure due diligence can protect you from a $200,000–$500,000 mistake. That’s a 25x–60x return on your diligence spend.

What to Do If You Find Problems

Finding infrastructure issues doesn’t automatically kill a deal — it changes the negotiation.

If you find $150,000 in water line work that needs to happen in the next 2–3 years, you have two options:

1. Requote the deal — reduce your offer by the cost of the work, or ask the seller to cure it pre-close
2. Price it into your underwriting — model the CapEx out over 3 years and see if the deal still pencils at the revised NOI

What you don’t do is ignore it and hope it works out. It won’t.

The Bottom Line

Mobile home parks remain one of the best risk-adjusted investments in real estate — but only when you know what you’re buying. The infrastructure issues that burn investors are almost always discoverable with proper due diligence. The ones who get hurt are the ones who rushed the process, trusted the seller’s numbers, or hired the wrong inspectors.

Do the work upfront. The park that survives infrastructure scrutiny is the park worth owning.

Andrew Keel is the founder of Keel Team, one of the most active mobile home park operators in the Southeast. Keel Team specializes in direct-to-owner acquisitions in NC, TN, GA, and SC.