Updated August 16, 2026
Most first-time multifamily buyers budget for the down payment and the closing costs and are then surprised by a third number: what it costs to find out whether the building is what the offering memorandum says. Due diligence is money you spend before you own anything, and on a deal that dies you do not get it back. Budgeting for it properly is the difference between walking away from a bad building with a bruise and walking away unable to afford the next look.
Physical inspection. A property condition assessment covering roof, structure, plumbing, electrical, HVAC and common areas. On an older LA building this is the single most valuable report you will buy.
Sewer lateral scope. A camera down the line. On a pre-1978 building with original clay pipe, this one inspection routinely finds five-figure problems that no visual walkthrough would.
Phase I environmental. A records-and-inspection review your lender will almost certainly require. In Los Angeles the recurring findings are former dry cleaners, service stations, and historic oil production.
Seismic / probable maximum loss report. Ordered by the lender on most multifamily. It drives whether earthquake insurance becomes a requirement.
Appraisal. Lender-ordered, buyer-paid.
Zoning and permit research. Confirming the legal unit count, which is where unpermitted units surface.
Legal review. Purchase agreement, leases, the entity, and the compliance file.
Your own time, which is the cost nobody itemises and everybody pays.
These do not appear on a generic national checklist and they are where LA deals actually go wrong.
RSO registration and rent registry history. Pull it and reconcile it against the rent roll line by line. If the registry shows a lower rent than the rent roll, the rent roll is the problem — and a rent that has to roll back, capitalized at a market cap rate, is a five-figure valuation hit on one unit.
LAHD compliance record. Open citations, systematic code enforcement inspection history, and whether the building has ever been in the Rent Escrow Account Program.
Soft-story retrofit status. Complete, in progress, or not started, with permits to prove it.
Tenant estoppel certificates. Signed by tenants confirming rent, deposit, lease terms and any side agreements. This is the document that catches what the rent roll does not say.
Insurance quotes for you, not the seller's premium. In the current market this is the item most likely to move your underwriting, and it should be obtained early rather than at the end.
Sellers push for short diligence periods and buyers ask for long ones, and the honest middle depends on what the seller has prepared in advance.
Ask what the seller has already produced before you negotiate the period. A seller with a complete file is offering you speed; a seller without one is asking you to fund the discovery.
Sequence it by kill risk. Spend first on whatever is most likely to end the deal. On an older LA building that usually means the registry reconciliation and the sewer scope — both cheap relative to what they find. Do not order the expensive reports until the cheap ones have cleared.
Read the seller's reports, then verify selectively. A seller who provides a recent condition report has given you a map. Use it to target your own inspection rather than duplicating it wholesale.
Get the insurance quote in week one. It is free, it is fast, and it moves the number more than anything else you will order.
Do not skip the sewer scope to save money. It is the highest-yield inspection per dollar on pre-1978 LA stock, and the failure it finds is one you would otherwise discover as an owner.
Not everything you find is worth renegotiating, and buyers who retrade on cosmetics train sellers to distrust them.
Worth a real conversation: a genuine capital item at end of life, an unfinished mandatory retrofit, a registry discrepancy, unpermitted units, an open code case, or an insurance cost materially above what the operating statement showed.
Not worth it: normal wear, cosmetic condition, and anything visible on the tour that you priced when you bid.
The distinction matters because your credibility is an asset. A buyer who raises only real items gets taken seriously on them.
Who pays for due diligence?
The buyer, in nearly all cases, and it is not refundable if the deal dies. That is the whole reason to sequence spending by kill risk.
Can I ask the seller for their reports?
Yes, and many have them. A seller who has run a pre-listing condition report will usually share it. Treat it as a starting map rather than a substitute for your own work — it was commissioned by the other side.
What is the single most valuable thing to check on an LA building?
The rent registry against the rent roll. It costs almost nothing, it is the fastest way to find out whether the income you are buying is real, and it is the item that most often changes a price.
How much diligence can I do before going into contract?
More than most buyers realize. Financials, leases, registry history and public records are all reviewable before you tie up a deposit. Physical access generally requires being in contract, but the paperwork does not.
Due diligence is not a formality you complete on the way to closing. It is the only chance you get to find out what you are buying while you can still change your mind — and on an older Los Angeles building, the cheap items find the expensive problems. Sequence it that way and the budget takes care of itself.
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