Due Diligence Period Real Estate: What to Order, and When

Subtract before you plan. A ten-day due diligence period does not hold ten usable days, and a radon test is the cleanest way to see why. EPA's Home Buyer's and Seller's Guide to Radon (EPA 402/K-24/001, March 2024 revised) gives three acceptable short-term tests for a real estate transaction, and the one EPA says best represents a seasonal average is also the slowest: windows shut for at least twelve hours before the device goes down, forty-eight hours of exposure, then a second forty-eight with an identical device immediately after the first. That is four and a half days before a lab has opened the envelope, on one line item — and none of it can start until somebody with a key has let an inspector in. The other two options finish in a single forty-eight hours, which makes the choice a day-one scheduling decision rather than a day-six discovery.

Meanwhile the appraisal has not been ordered, because you are not allowed to pay for it yet.

This is the part of the transaction that reads like a to-do list and behaves like a dependency graph. The whole-calendar view — every deadline in a standard contract, laid on a day axis — is in the 45-day map. What follows is only the front end of it: the first seven to ten days, in the order the work has to be commissioned rather than the order it gets completed.

Forms and regulations below were read on 27 September 2026. Federal text is the 1 August 2026 edition of the CFR, pulled from the eCFR versioner API rather than a live page.

First, find out what your contract calls this and which paragraph defines it

There is no national name for the window, and the naming difference is not cosmetic — it tells you which paragraph to open.

North Carolina's Offer to Purchase and Contract, Standard Form 2-T (Revised 7/2025) defines a Due Diligence Period as the period beginning on the Effective Date and extending through 5:00 p.m. on a date the parties fill in — or, on the alternate line, a stated number of days from the Effective Date, ending at 5:00 p.m. on the last day. TIME IS OF THE ESSENCE is printed inside the definition itself.

Texas calls it an Option Period. In the One to Four Family Residential Contract (Resale), TREC No. 20-19 (page footers dated 05-04-2026), paragraph 5B grants the buyer the unrestricted right to terminate by giving notice within a blank number of days after the Effective Date, and notices under that paragraph must be given by 5:00 p.m. local time where the property sits.

Florida calls it an Inspection Period and prints a fallback. Paragraph 12(a) of the redlined AS IS Residential Contract for Sale and Purchase (FloridaRealtors/FloridaBar-ASIS-7x) posted by Florida Realtors reads: Buyer shall have ______ (if left blank, then 15) days after Effective Date ("Inspection Period"), with termination in the buyer's sole discretion by written notice before it expires.

California has no single named period. The Department of Real Estate's Reference Book chapter on residential contract provisions describes the usual shape as 3 days to get the deposit into escrow, 7 days to complete loan applications and provide verification of funds, and 17 days to inspect and investigate, with the seller typically delivering required disclosures inside 7 days — and any contingency removal in writing on a separate form.

Whichever applies, do one thing before you dial anybody: write the expiry down as an actual date at the top of the page, not as a number of days. Ten days is an arithmetic problem with an argument attached. Tuesday 6 October is not. Add the hour if your form prints one — North Carolina and Texas both say 5:00 p.m., Texas in the local time where the property sits. Florida's form prints no hour at all: STANDARD F says calendar days are used, and any period ending on a Saturday, Sunday or national legal public holiday extends to the next day that is none of those. Which paragraph governs the count in your own contract, and what happens if the last day is a weekend, is worth confirming with whoever prepared it before you rely on your own arithmetic. What each of those conditions actually buys you is a separate question, answered in what each contingency covers.

The first delivery is money, and in two states it is what buys the exit

Before any inspector exists there is a payment with its own deadline, and in two of these forms that payment is a condition of the right you think you already have.

North Carolina's Due Diligence Fee sits on the same page as the price, made payable and delivered to the seller on the Effective Date — not to escrow, not within three days. Paragraph 4(g) then opens with the condition attached to it: Provided that Buyer has delivered any agreed-upon Due Diligence Fee, the buyer may terminate for any reason or no reason during the period. Texas reaches the same place from the other direction. Paragraph 5A puts the earnest money and the option fee with the escrow agent within 3 days of the Effective Date, and 5D says that if no dollar amount is stated as the option fee, or it is not delivered in time, Buyer shall not have the unrestricted right to terminate this contract under this paragraph 5. A printed Option Period and a working one are not the same thing, and the blank that decides it is on the first page.

Florida's second deposit is the one to diary rather than the first. When that blank is left empty the additional deposit is due 10 days after the Effective Date, which lands inside a default 15-day Inspection Period — money going in while you are still deciding whether to leave.

So the first act of due diligence is a bank transfer with a receipt, and the receipt is worth asking for by email the same day. Which deposit goes where, in what order, and what each one is called form by form is the opening stretch of the 45-day map; what matters this week is only that it is due before the first phone call. Where the money then sits, and who can move it, is a question about the escrow holder rather than about your contract.

Six pieces of information start the lender's clock, and nothing starts without them

The appraisal is the longest item in this window and the only one you cannot order. What you can do is start the chain that lets somebody else order it, and the chain has a defined first link.

Under 12 CFR 1026.2(a)(3)(ii), for these purposes an application consists of exactly six things: your name, your income, your Social Security number to obtain a credit report, the property address, an estimate of the value of the property, and the mortgage loan amount sought. Not a pre-approval letter, not a folder of pay stubs. Six fields. Until all six are with the lender, the timing rules below have not begun.

Once they are, three provisions decide the earliest date an appraisal fee can be charged to you — which, in practice, is when the order goes out, though nothing in the rule stops a lender from ordering earlier at its own cost:

1. 1026.19(e)(1)(iii)(A) — the Loan Estimate must be delivered or placed in the mail no later than the third business day after the creditor receives your application.
2. 1026.19(e)(2)(i)(A) — neither the creditor nor anyone else may impose a fee on you in connection with the application before you have received the Loan Estimate and indicated an intent to proceed. The only carve-out, in (e)(2)(i)(B), is a bona fide and reasonable fee for pulling your credit report.
3. 1026.19(e)(1)(iv) — if the Loan Estimate is not provided in person, you are considered to have received it three business days after it is delivered or placed in the mail.

Now the part that surprises people who have read the rule once. Business day means two different things inside that same subsection. 1026.2(a)(6) gives the general definition — a day on which the creditor's offices are open to the public for carrying on substantially all of its business functions — and then lists specific provisions where it instead means all calendar days except Sundays and the legal public holidays in 5 U.S.C. 6103(a). The deemed-receipt clause (e)(1)(iv) and the fee restriction (e)(2)(i)(A) are on that list. The three-day delivery deadline in (e)(1)(iii)(A) is not. One further wrinkle sits in the commentary to 2(a)(6): where the calendar-day rule applies, a holiday observed on another day because it fell on a weekend is still a business day. July 4 on a Saturday, offices shut on Friday July 3, and July 3 counts.

Run it on a calendar. Application complete Monday. The Loan Estimate is due by Thursday, counting days the lender's office is open. It goes out Thursday by email. Deemed receipt counts Friday, Saturday and Monday — Saturday counts here — so you are deemed to have received it Monday, a week into the transaction. Only then can the appraisal fee be charged, which is when the order goes out.

That is the whole reason an appraisal inspection so often happens after a ten-day window has closed. It is also the one place on this page where a single email shortens the chain, and the authority for that is in the commentary rather than the rule. Comment 19(e)(1)(iv)-2 says a creditor may instead rely on evidence that you received the disclosures earlier, and gives the case squarely: emailed at 1 p.m. on a Tuesday, acknowledged by the consumer at 5 p.m. the same Tuesday, received Tuesday. So open the Loan Estimate the day it arrives, reply confirming receipt with the date, and say in the same message that you intend to proceed. Three days of the lag can come off — at the creditor's option, which is worth knowing before you count on it. One more document rides that same timetable. 1026.19(e)(1)(vi)(B) requires the Loan Estimate itself to identify the settlement services you are permitted to shop for, and (e)(1)(vi)(C) requires a written list of available providers for each of them — delivered separately from the Loan Estimate, but on the timing in (e)(1)(iii). That list is what decides which fees can legally move later.

Work backwards from the last day, not forward from today

Everything else is a scheduling problem with somebody else's calendar in it. The useful column is not how long does this take but whose clock is it.

Two entries need a caveat rather than a number. Which specialist inspections are worth ordering at all is a judgment call with state-specific paperwork behind it, set out in sewer, radon and termite: which to order. And the survey question is genuinely a checkbox: paragraph 6C of TREC 20-19 offers three boxes — seller furnishes an existing survey with a T-47 affidavit or T-47.1 declaration within a blank number of days, or the buyer may obtain a new survey at buyer's expense within a blank number of days, or the seller furnishes a new one. Which box is marked changes who you are waiting on, and ordering one too early has its own cost — a survey drawn before the exception documents arrive is described in the survey's own timing problem.

The pattern across the table: the long items are long for reasons printed in a standard or a statute, and none of them care what your contract says. A form can give you ten days. It cannot make a 48-hour test finish in 24.

Some of this needs permission you do not automatically have

Access is broad. Testing is not.

TREC 20-19 paragraph 7A gives the buyer and the buyer's agents access at reasonable times, allows inspections by inspectors licensed by TREC or otherwise permitted by law, and obliges the seller to turn existing utilities on immediately and keep them on while the contract is in effect. Then one sentence narrows it: Any hydrostatic testing must be separately authorized by Seller in writing.

That sentence is why a sewer and drain-line test can fail to happen inside an option period without anybody refusing anything. The request goes out on day six, the listing agent forwards it, the seller is travelling, and the authorization arrives after the plumber's slot has gone. Put it in the day-one message, alongside the request to have water and power on.

North Carolina attaches an obligation on the other side of the same coin, and it carries an exception worth reading before you book anyone. Paragraph 4(e) makes the buyer promptly repair, at the buyer's expense, any damage to the property resulting from the activities of the buyer and the buyer's agents and contractors — but expressly not damage caused by accepted practices either approved by the N.C. Home Inspector Licensure Board or applicable to any other N.C. licensed professional performing reasonable appraisals, tests, surveys, examinations and inspections. So a standard inspection done to standard by a licensed person is carved out; work outside that is not. What survives is the obligation itself: the form says the repair obligation shall survive any termination of the contract, so walking away does not discharge whatever falls outside the carve-out. Which side of that line a particular test sits on is a question for the licensed person doing it, asked before they start.

The title commitment usually arrives after this window has closed

This is the structural mismatch people discover late: the document that tells you what you are actually buying is not on the due diligence clock at all.

TREC 20-19 paragraph 6B gives the seller 20 days after the title company receives a copy of the contract to furnish the commitment and legible copies of the exception documents — those copies at the buyer's expense, which is a line item people do not budget for. If they are late, the time is automatically extended up to 15 further days, or to 3 days before the closing date, whichever is earlier. A seven-day option period can therefore expire before the commitment exists, and a ten-day one usually does.

Florida measures it from the other end. Paragraph 9(c) of the AS IS contract sets the Title Evidence Deadline at at least 15 days prior to Closing Date when the blank is left empty — 5 days for a cash deal. In a 45-day contract that puts the commitment around day 30, a fortnight after a 15-day Inspection Period has closed.

The objection clock is separate again. TREC paragraph 6D requires the buyer to object in writing by the earlier of the closing date or a blank number of days after receiving the commitment, exception documents and survey — so it starts on receipt, not on the Effective Date. Failure to object within it waives the right to object, with one exception the form names: the requirements in Schedule C of the commitment are not waived. Reading what those exceptions do to your ownership is a job of its own: what Schedule B stops insuring.

Practical consequence for this week: do not treat the commitment as something you are waiting for during due diligence. Ask on day one when the title company received the contract, because that date starts the 20 days in Texas, and put the resulting date on the same page as your 5 p.m. deadline — in a different column.

Repairs are inside the window, not the sequel to it

The most common way a well-run first week still fails is arithmetic at the back end. The report lands on day eight, the repair request goes out on day nine, and the window shuts at 5 p.m. on day ten with no answer in it.

North Carolina's form addresses this in the text rather than leaving it to advice. Paragraph 4(d) tells the buyer, in capitals, that unless the parties agree otherwise the property is being sold in its current condition; that the seller may, but is not required to, engage in repair negotiations; and that the buyer is strongly advised to make repair requests in sufficient time to allow negotiations to be concluded prior to the expiration of the Due Diligence Period. Any agreement reached has to be in writing and signed.

Paragraph 4(a) of the same form supplies the reason it matters so much there: There is no loan or appraisal contingency in this Contract. Whatever you are going to learn and whatever you are going to negotiate has to fit inside this one window, because after it closes the deposit is exposed. Texas reaches a similar place by a different route — the unrestricted right to terminate lives in the Option Period and nowhere else.

So build the schedule backwards from a repair conversation, not from a report. If negotiation needs two or three days, the report has to be in your hands by day six or seven, which means the inspection happens by day four or five, which means the call goes out on day one. That chain is the entire argument of this page.

An extension is a signed form, and the seller is allowed to say no

Nothing in these contracts extends because a lab is slow or a plumber cancelled.

Paragraph 4 of Form 2-T states it plainly: terminate before the Due Diligence Period expires unless you can obtain a written extension from the seller, and Seller is not obligated to grant an extension. Terminate outside the period and you may lose the earnest money deposit — while the due diligence fee, already the seller's property since the Effective Date, does not come back either. The form does allow investigation to continue after the period ends; what ends is the cheap exit.

California's version of the same idea runs through notices rather than expiry. The DRE chapter states the underlying rule outright — the contract says time is of the essence, and the time for performance can be extended, or any other provision modified, only by a writing signed by both buyer and seller — and describes a Notice to Perform, typically allowing 24 hours, when one side has not performed. An Extension of Time Addendum is one of the C.A.R. forms the chapter lists. Texas needs an amendment. Three mechanisms, one rule underneath: a deadline moves only on paper signed by both sides.

Which is why the seller's disclosure deserves a line here. TREC paragraph 7B(2) gives the buyer, when the notice has not yet been received, the right to terminate at any time before closing if it never arrives — and if the seller does deliver it, a right to terminate for any reason within 7 days after receipt or before closing, whichever comes first. That clock starts on a document arriving in your inbox, on a day nobody schedules. It is worth knowing it exists before you spend the last of the option period arguing about a water heater; how to read the answers on that form is a separate exercise in blanks.

The first afternoon, in the order it has to happen

Nine items, roughly forty minutes, and every one of them exists to start a clock somebody else controls.

1. Ask for the Effective Date in writing. Every date below hangs off it and it is not the day you signed.
2. Send the fee or deposit that is due first, then ask escrow — or the seller's agent, in North Carolina — to confirm receipt by email. Check the option fee amount is actually written in the blank.
3. Write the expiry as a date and an hour at the top of one page. Add the delivery deadline for the second deposit if your form has one.
4. Give the lender the six fields from 1026.2(a)(3)(ii) in a single message. Ask when the Loan Estimate will go out and whether it will be delivered electronically.
5. Book the general inspection, and in the same call ask which specialist work has to be booked simultaneously rather than after the report.
6. Ask the seller in writing for utilities on and for any separate authorization your tests need — hydrostatic testing in Texas, roof or attic access, gate and alarm codes.
7. Request the association documents, with the fee and the turnaround time, from whoever holds them rather than from whoever mentioned them.
8. Read the survey checkbox in your own contract and act on whichever box is marked.
9. Ask what date the title company received the contract. In Texas that date, not yours, starts the twenty days.

Then open the Loan Estimate the day it arrives, confirm receipt, and say you intend to proceed. Of everything on this page, that reply is the cheapest three days you will find.