My engineer filed the final plat and the county rejected it three weeks later over a drainage study that nobody flagged during preliminary approval

The drainage standards update is the core problem here, and the assumption doing the most work in your engineer's position is that "implied blessing" from preliminary approval carries forward when the governing standards change mid-process. It frequently does not. Preliminary plat approval locks in the design against the rules in effect at that filing date, but final plat review is a fresh technical check, and if the county adopted new drainage standards between your two filing dates, they are almost always entitled to apply the new standard at final. That is not negligence on anyone's part necessarily, though it is worth asking your engineer directly whether the October adoption was publicly noticed and whether a competent practitioner in that county should have caught it before filing.

On the clock question: the conflict between your engineer and the county clerk is a real problem. County-level plat review timelines in Texas are governed by Chapter 212 of the Local Government Code, but individual counties have procedural rules layered on top, and whether a rejected final plat resets the statutory clock or continues it depends on how the rejection is classified, deficiency versus denial. Those are different procedural postures with different timelines. Get that answer in writing from the county's planning department, not over the phone. If your engineer cannot get you a written answer, a Texas land use attorney should make one call. That is a licensed professional question and I will leave it there.

The $8,400 revised study is probably not negotiable. The carry cost is real: ten weeks on $310k at 9.5% is roughly $5,700 in interest, so you are looking at a $14,000 swing off a standards change nobody surfaced.

The question I would put to your engineer in writing: on what date did Bastrop County adopt the updated drainage standards, and when was that adoption publicly available relative to your final plat filing date?

The clock question is the one that actually costs you money, and your engineer and the county giving different answers means you need the county's response in writing before you spend the $8,400, because if they restart the full review period you are looking at more carry cost than the study itself.

The risk nobody has flagged is engineer liability. If the October standards adoption was a public notice item, a competent engineer filing a final plat in January had an obligation to catch it, and that $8,400 revision plus the carry cost on ten weeks of a $310k loan at 9.5% is roughly $12,900 all in, which is a number worth putting in a letter to the engineer before you just absorb it as a project cost.

What does your engineering contract say about errors and omissions, and did the county post the October standards update with any formal effective date language you can reference?

Your engineer's job is literally to track those updates, and "October adoption, January filing" is a three-month window where a competent engineer catches that before you pay filing fees. I would have that conversation with him directly about who eats the $8,400 because that is a real argument to make.

On the clock question, in my experience county offices will tell you one thing on the phone and do another thing entirely once the revised study lands on the right desk, so I would not trust either answer until you have something in writing from the planning department. That said, Bastrop specifically has been inconsistent on this, from what I have heard from people working parcels out there.

What does your contract with the engineer actually say about errors and omissions, and does he carry E&O insurance?

The engineer's professional obligation in Texas generally covers monitoring adopted amendments to county drainage criteria, and Bastrop County's drainage design manual updates are public record the moment they pass. Whether your engineer had actual notice is a separate question from whether they had constructive notice, and that distinction matters if you want to pursue an E&O claim. I would pull the county's adoption date, compare it to your engineer's last substantive submission before January, and ask in writing what monitoring process the firm uses for mid-project standards changes. If the gap is clean, meaning the update posted before the final plat package was assembled, you have a legitimate conversation about who absorbs the $8,400. That does not mean you will recover it, but the basis exists. On the county process, the conflict you heard between your engineer and the county clerk is worth resolving at the department director level rather than the front desk, because Texas Local Government Code gives counties some discretion on how they handle resubmittals triggered by their own standards changes rather than applicant error.

The interest carry is real. Ten weeks on $310k at 9.5% is roughly $5,700, and combined with the study cost you are looking at $14,100 in friction before you sell a single lot. What I would want to know is what your lot absorption timeline looked like before this hit, because that number changes how hard to push on the timeline relief. If you were planning to close all six lots within ninety days of final plat, ten weeks of delay compresses your sell-off window and potentially forces a price concession to move inventory before carrying costs compound further. If you had a phased sale plan with six to twelve months of runway, the carry is annoying but not structurally dangerous. What is the loan maturity date relative to your original projected sell-out?

The conflict between what your engineer said and what the county office told you over the phone is the part I'd press hardest right now, because a verbal answer from a counter clerk is not the same as what the actual review coordinator puts in writing, and those two people are often not talking to each other.

In my experience with Columbus Township on a 9-lot split, the clock restarted when we resubmitted anything marked as a revision, even a minor one, so I would get that "picks up where it left off" answer from your engineer confirmed in an email from an actual county planner before you bank on the shorter timeline.

What does your preliminary approval letter say about applicability of standards in effect at time of final submittal, because some counties write that in and some don't?

The gap between preliminary and final plat approval is where regulatory changes can land, and Texas does not freeze county engineering standards for projects mid-process the way some states do with vested rights statutes. Bastrop County's October adoption technically applied to any final plat filed after that date, so the rejection is procedurally defensible even if it feels like a moving target. What I would want to know before accepting the $8,400 and ten weeks as fixed costs is whether your engineer's contract included an obligation to monitor adopted standards updates during the hold period, because if it did, that cost reallocation conversation is worth having in writing before you authorize the revised study. On the clock question, counties in Texas commonly treat a rejected final plat as a new submission for review timeline purposes, but some allow a resubmission track with a shorter turnaround if the rejection was narrow and the original file stays open. Your engineer saying one thing and the county clerk saying another means neither answer is confirmed, and the person who actually controls that answer is the county's development services director or the reviewing engineer at the county level, not the front office.

Before I authorized a dollar of the revised study, I would pull the county's adopted engineering standards document with the October effective date and compare it line by line against what the original drainage study submitted. If the gap is limited to one or two updated calculations rather than a full methodology change, there is room to argue for a targeted amendment rather than a full resubmission, which compresses both cost and timeline. I would also ask the county in writing whether a resubmission under the corrected study resets the statutory review clock or runs on the original file number, because getting that answer verbally from two different people is useless when your carry cost is running. The $4,900 or so in added interest over ten weeks is real but it is the floor, and the actual number