BOMA 2024 vs 2017: CAM Billing Changes

On a 250,000 RSF office building, adopting BOMA 2024 produced an additional $445,500 in annual NOI — from no new tenants, no capex, and no rent bumps. Just different math. For property controllers, wrong denominators produce wrong tenant bills, which produce disputes and clawbacks.

What Changed: BOMA 2017 vs. BOMA 2024

Net effect across a typical portfolio: 2–5% RSF increase per building.

What This Means for Your Pro-Rata Calculations

A larger RSF denominator changes every tenant's pro-rata share — even if the CAM pool itself doesn't grow. Two tenants with identical leases can end up with different bills if one lease was signed under 2017 measurements and the other under 2024 measurements. That gap isn't a rounding error; it's a structural mismatch baked into your billing system.

Mixed-vintage lease books are the real landmine. When you have 2017-era leases sitting beside tenants whose space was certified under 2024 methodology, you're running two different denominators in the same pool without realizing it. That mismatch compounds every reconciliation cycle — year one it's a rounding issue, year three it's a dispute, year five it's an audit demand from counsel.

When the denominator shifts due to BOMA re-measurement, CAMAudit automatically detects the change and generates a denominator change audit report showing exactly how each tenant's pro-rata share moved and by how much. See our guide on why pro-rata shares change for the full breakdown of denominator shift triggers and documentation requirements.

The place this surfaces earliest is GL coding. If your expense categories don't map cleanly to your measurement standard, controllers end up manually reconciling line items that should close automatically. Before you re-measure or renegotiate, lock down your coding discipline first — see the GL Coding Guide for the specific categories where 2024 changes the inclusion/exclusion calculus.

The Non-Allocated Tenant Area Problem

BOMA 2024 reclassified balconies and rooftop terraces as "Non-Allocated Tenant Areas" — and that one change breaks the math in most mixed-vintage lease books.

Under BOMA 2017, balconies and terraces carried a load factor. The common area overhead was distributed across those spaces the same way it was distributed across interior tenant areas. Under BOMA 2024, these spaces are measured at 100% of their actual area with no load factor applied. The practical effect: the same physical space now produces a different rentable square footage number depending on which standard you use to measure it.

That difference matters the moment you have leases signed under both standards in the same building. A tenant whose lease was executed under BOMA 2017 measurements has a pro-rata share calculated on one denominator. A tenant whose lease was executed or re-measured under BOMA 2024 has a share calculated on a different denominator. Add them together and the shares don't sum to 100%. This is not a rounding error — it is a mathematical consequence of running two measurement methodologies in parallel.

Most billing systems assume a single denominator for the entire building. When the assumption breaks, every tenant's allocation is wrong — and the errors compound with each reconciliation cycle. The fix requires identifying which leases use which standard, calculating separate denominators, and reconciling the gap. CAMAudit flags this mismatch automatically from your existing GL export.

What You Need to Do Now

Sources

1. BOMA 2024 Office Standard (ANSI/BOMA Z65.1-2024) — BOMA Standards Portal
2. "2-5% RSF increase from BOMA 2024 adoption" — Sources & methodology
3. Gensler BOMA 2024 analysis — Gensler
4. Building Engines BOMA transition guidance — Building Engines