Underwriting a 10–15% Location Discount (Train Tracks + Drainage Ditch) SA,TX

San Antonio, Texas
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Underwriting a 10–15% Location Discount (Train Tracks + Drainage Ditch) SA,TX

Micah BolchPro Member
San Antonio TX · Member since 2026 · 27 posts · 10 votes

Hey BiggerPockets Community,

I’m underwriting a single-family off-market deal in Northwest San Antonio (78249 zip code, Northside ISD) and would love to get input from local TX investors and experienced flippers on how you discount for specific site nuisances.

The Property Profile

  • Layout: 3 Bed / 2.5 Bath | 1,252 SF | Built in 1975

  • Lot Size: ~0.32 Acres (Unusually large lot for this specific subdivision)

  • Schools: Strong Northside ISD ratings (Elementary 7/10, Middle 7/10, High School 6/10)

  • Condition: Full gut rehab needed (deferred maintenance, abandoned plumbing leak remediation, siding replacement, full interior remodel, fence).

The Two Site & Location Hazards

  1. Rear Freight Train Tracks: The back alley directly borders an active freight rail line.

  2. Left Drainage Ditch: Municipal storm runoff ditch runs along the left lot line. (Verified FEMA Zone X — minimal flood hazard, so no mandatory flood insurance required).

The ARV & Discount Logic

Subdivision comps without location defects put pristine 3/2.5 turnkeys in the $250,000 range.

Because of the tracks and drainage ditch, I’m discounting the After Repair Value by 10% to 15%, which brings the realistic resale baseline down to ~$225,000 (matching the current tax assessment valuation of $229,780).

My thought process is that the massive 0.32-acre lot gives a great buffer, and double-pane vinyl windows + 6ft cedar fencing will mitigate acoustic issues, but the discount is necessary to account for a slightly reduced buyer pool.

Underwriting Breakdown:

  • Target Resale / Baseline ARV: $229,780

  • 70% Buy Box Target: $160,846

  • Estimated Rehab Budget (Investor Rates): $65,000 ($51/SF heavy gut, mechanicals, siding, LVP, kitchen/baths, fence)

  • All-In Purchase Target: $95,846

  • Projected Gross Margin / Equity: ~$68,900

  • Alternative Exit (Rental): Projecting $1,850–$1,950/mo rent (UTSA / USAA corridor demand).

Questions for the Pros:

  1. Discount Rate: Is 10–15% sufficient off top-of-market comps for rear rail line exposure in 78249, or would you hit it harder in today's market?

  2. Buyer Perception: For those flipping near rail lines in SA, have double-pane windows and privacy fencing been enough to move the property smoothly at the discounted ARV?

  3. Rehab Estimate: Does $65k sound realistic for a 1,250 SF heavy cosmetic + siding + mechanical rehab using local sub crews?

She accepted $90,000 which sounds high to me.

Appreciate any insights or feedback from the local San Antonio market!

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Drew SygitBusiness Member
Property Manager · Royal Oak, MI · Member since 2012 · 12k+ posts · 9k+ votes
3d

How many other nearby properties back to the same tracks?

Do a neighborhood deep dive to see when all their last sales amounts & dates were.

If you have MLS access, you should be able to also look at the entire area to determine average sales price when each property sold.

That will give you a way better understanding of a target discount as opposed to your current "guess".

Recommend also paying attention to DOM for each sale as that would be my biggest concern - what percentage of buyers will accept the train tracks in their backyard?

  • So, the DOM to sell probably MORE important than the price.

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  • Matthew MorrowBusiness Member
    Investor · PA - NY - NJ · Member since 2019 · 655 posts · 225 votes
    3d

    @Micah Bolch The rail line is where I'd be most conservative. A freight train is something every showing hears. I'd have a local agent pull sold comps that actually back onto tracks before you settle on 10-15%. You make your money when you buy, so if the numbers only work with everything going right, push back. And on a 1975 house, put at least 10% contingency on top of the $65K.

    [email protected]484-791-6200
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  • Drew SygitBusiness Member
    Property Manager · Royal Oak, MI · Member since 2012 · 12k+ posts · 9k+ votes
    3d

    How many other nearby properties back to the same tracks?

    Do a neighborhood deep dive to see when all their last sales amounts & dates were.

    If you have MLS access, you should be able to also look at the entire area to determine average sales price when each property sold.

    That will give you a way better understanding of a target discount as opposed to your current "guess".

    Recommend also paying attention to DOM for each sale as that would be my biggest concern - what percentage of buyers will accept the train tracks in their backyard?

    • So, the DOM to sell probably MORE important than the price.

    [email protected]248-209-6824
    Logical Property Management4.9460 Reviews
    WebsiteView Page
    1Reply
  • Nyisha Walton
    Lender · Houston, TX · Member since 2026 · 35 posts · 9 votes
    3d

    Hi Micah, nice breakdown. If you plan to finance it, we do fix and flip loans that cover part of the purchase and the rehab with draws, plus a DSCR refi if you keep it as a rental. When do you close?

    0Reply
  • Hampton Rogers
    Real Estate Consultant · Chattanooga TN · Member since 2026 · 22 posts · 8 votes
    3d

    Micah, interesting situation. I'd be careful about applying a blanket 10–15% discount before understanding exactly what you're dealing with.

    The rail line is one issue, but that drainage ditch raises a different set of questions. Is there a recorded drainage easement? Does it affect the usable portion of the lot? And is there any documented flooding history?

    I'd want to separate what we know about the property from what we're assuming before putting a number on the risk. Have you been able to dig into the property records yet?

    0Reply
  • Divin KanyamaBusiness Member
    Accountant · Seattle, WA · Member since 2025 · 481 posts · 200 votes
    2d

    The main concern is that a flat 10%–15% discount may be too theoretical for two permanent site nuisances, @Micah Bolch. The strongest evidence would be closed sales backing or facing the same rail line and drainage channel—not tax assessment or clean interior-subdivision comps. Windows and fencing may improve the experience inside, but they will not remove vibration, horn noise, outdoor noise, safety concerns, or the visual objection at resale. The larger lot helps only if buyers perceive it as usable and the drainage easement does not limit that use.

    The $65,000 rehab also sounds tight for a true gut with leak remediation, plumbing uncertainty, mechanicals, siding, kitchen, baths, and fencing. Obtain detailed trade bids and carry a meaningful contingency, plus financing, holding, closing, commissions, taxes, insurance, and utilities. At a $90,000 purchase price, there appears to be very little room between the buy-box target and the offer before those costs or a lower resale are considered. I would validate the rental estimate with rail-adjacent leases, inspect the ditch and easements carefully, and stress-test both a lower ARV and a larger rehab. If the deal stops working under modest downside assumptions, the accepted price is probably too high.

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  • Ethan Toscano
    Technology · San Antonio Texas · Member since 2026 · 1 post · 0 votes
    2d

    Hey Micah,

    Just want to give my input partially of what you mentioned.

    For the ditch, pull the recorded plat for it. If there's a drainage easement, it can eat the usable yard and limit fencing or additions. Zone X just means insurance isn't required, not zero risk.

    Also, the 0.32 acres may be worth more than the house? Depending on the zoning and frontage, it could allow an ADU, or sometimes a split. Worth checking before you commit to a straight flip.

    I'm building a San Antonio site-analysis map that checks zoning, lot fit, flood and rail distance on a lot. Happy to run this one if you want to DM the address, if not no worries you can choose to see the area yourself if you’d like on atlasstellardynamics.com , any feedback helps.

    Thanks,

    0Reply
  • Jeremy White
    Member since 2026 · 29 posts · 14 votes
    6h

    Micah, the permit and code history on the address is what decides whether a $65K full gut number holds. For finding your next deals, we gather San Antonio residential permits and the Bexar County tax foreclosure sale list from official city records and public records, one-time, not a subscription. Are you sourcing in 78249 or across the city?

    0Reply
  • Noah WrightBusiness Member
    USA, Nationwide · Member since 2024 · 230 posts · 102 votes
    5h

    Checking the flood zone before making an offer was the right call. As a placeholder for your offer math, 10 to 15 percent isn't unreasonable, but it isn't the number that sizes the loan. Most fix and flip lenders lend off their own appraiser's ARV, and that appraiser only takes a deduction for the tracks if nearby track-backed sales support it, so your ARV is only as good as the comps the appraiser can find. On the rehab, the lenders I shop go through the scope and budget line by line, most want a contingency in it, and draws usually only pay for finished work, so a short budget becomes your cash mid-project. Are you flipping or holding? That decides whether your exit rides on a buyer's appraisal or on the rent.

    [email protected]737-773-3717
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