Grounds & Site

Cluster Mailboxes (CBUs): Useful Life & Replacement Cost for HOAs

USPS-approved cluster box units (CBUs) typically last 15-25 years and cost about $2,000-$4,500 per unit to replace installed. The 8-16 door unit itself runs roughly $1,600-$3,500, with pedestal anchoring, concrete pad work, and labor adding $500-$1,000 or more. Salt air, vandalism, and lock wear are the main drivers of early replacement.

Last verified 2026-07-06

Typical useful life

1525 years

2026 replacement cost

$2,000$4,500

per unit (8-16 doors), national range

Typical HOA quantity

8 CBU units

Reserve budgeting

Count every CBU on the property and budget per unit, not per project — boards routinely forget concrete pads ($10-$12 per sq ft), old-unit removal, USPS site approval, and rekeying/key distribution, which can add 25-50% to the sticker price. Large communities can phase replacement over 2-3 years, but keeping a consistent model simplifies USPS coordination.

Extending its life

Lubricate locks and hinges annually, touch up powder-coat scratches before rust starts, and keep the concrete pad draining away from the pedestal base. Promptly repairing vandalized doors and parcel lockers prevents forced-entry damage from spreading and can push units toward the 25-year end of the range.

Regional variation

Coastal and high-humidity regions shorten CBU life through corrosion, and dense urban markets add 15-30% to installation labor versus national averages.

Estimate your cluster mailboxes (cbus) budget

National 2026 ranges · verify with local bids.

Typical small HOA: 8 CBU units

Replacement cost range$16,000$36,000
Suggested annual set-aside$640$2,400/yr

Set-aside = replacement cost ÷ useful life (1525 years). A new installation funds toward the long end; an aging one needs catch-up funding — run the full calculator for that.

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Cluster Mailboxes (CBUs) questions, answered

Sources

Retrieved and verified 2026-07-06. National planning ranges — local bids govern. Informational only; not engineering, legal, or financial advice, and not a substitute for a professional reserve study. Report a data issue.

Put cluster mailboxes (cbus) in your reserve plan

Add it to the free calculator with typical life and cost pre-filled, then see what your community should contribute each year.

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