Guadalupe-Blanco River Authority Regional Laboratory

At a glance

What it is certified to test

2 of the 9 common well tests on the TX list (see which)

Price

from $30 (Total coliform (Presence/Absence)), as printed on the lab’s website, read 14 Nov 2026

Turnaround

not stated on the state list or the lab’s website: ask when you order

Homeowner samples

yes (lab’s own website, read 14 Nov 2026)

Lab facts

Listed by

Texas (Texas Commission on Environmental Quality (TCEQ) - Laboratory Accreditation Program (NELAP))

Address

933 East Court Street, Seguin, TX 78155-5872 · Open in Google Maps

Phone

(830) 379-5822

Website

www.gbra.org/environmental/laboratory-service

Not on the state list: found and checked by us, 14 Nov 2026

Public / homeowner samples

Homeowner samples: yes (lab’s website)

Not stated in the list.

Certification record

Certificate ID

TX Lab ID T104704269

Issued by

Texas Commission on Environmental Quality (TCEQ) - Laboratory Accreditation Program (NELAP) (certification program)

Expiry on the list

5/31/2027 · expires in 197 days

List version

TCEQ Laboratory Approval Status - List of Accredited Laboratories (public database, Matrix: Drinking Water), version Live database, searched 2026-11-15 ("accurate as of the date and time of the search")

We fetched it

15 Nov 2026 (file SHA-256 d09853d6717d…) · open the state file

Tests on the state list

• Named on the official list The state list names this analyte (or a column for it) for this lab.
• Group-level certification Certified for a parent group (e.g. 'Inorganics') that includes this analyte. Confirm the specific test with the lab.
• Partial group certification The list marks the group as 'Partial'. Confirm this analyte with the lab.
• Subcontracted The lab sends this analyte to another accredited lab (MDH 'X*').

TCEQ lists 12 drinking-water analytes this lab is accredited for. TCEQ database: lab type Governmental; 'Commercial?' Yes; 'Is Primary?' Yes. Phone from TCEQ's PWS Laboratory Map Table (Last Updated 03/26/2026).

Homeowner service and turnaround (lab’s own website)

• Takes homeowner samples: yes. The lab’s site says: “A small team of dedicated employees manage the GBRA Lab to serve the public.” source
• Who collects: You collect it, or lab staff can. Sampling fee as printed: Environmental Sampling (2hr minimum) $120 per hour; Mileage Fee IRS Rate per mile. source
• By mail or courier: the lab says samples or kits can be shipped. Bacteria samples must reach the lab within its holding time.

From the lab’s own website, read 14 Nov 2026 and re-read by a second checker; next check due by 12 Feb 2027. Certification fields come from the state list only.

Prices the lab prints, compared

• Bacteria (coliform / E. coli) against other Texas labs: median $22.50 across 6 other labs that print a price on their own site; 4 of them charge less than $30.
• Nitrate against other Texas labs: median $35 across 3 other labs that print a price on their own site; 0 of them charge less than $30.

Comparison uses the lowest single-test price this lab prints; panels and ranges are left out. For comparison only, not a quote.

Nearest labs that take homeowner samples

1 other certified lab that takes homeowner samples is within 25 miles of this lab. Distances are straight-line from the address on the state list (approx. = ZIP-code centre). “Takes homeowner samples” comes from a state list column or the lab’s own website, as named.

Price and turnaround as printed on each lab’s own website and checked by a second reader; – = not published or not read yet.

Around this lab: Guadalupe County, TX

• Private wells: about 7,614 people, 5% of Guadalupe County’s 151,249 residents (USGS, 2015); rank 50 of 254 counties in Texas by people on wells.

• EPA radon zone (indoor air): Zone 3: low potential (average indoor radon may be less than 2 pCi/L). EPA says the zone map should not decide whether one home needs testing.
• Arsenic above 10 µg/L (USGS model): about 64 private-well users (95% range 53 to 77; 2010 base), rank 140 of 254 in the state. A screening estimate, not a measurement of any well.
• Older homes (Census ACS 2020–2024): 19% of 69,700 housing units were built before 1980, below the state share of 33%. Homes built before 1986 are more likely to have lead solder or fittings, so test tap water for lead there.
• PFAS in public water nearby (public supply, not your well): 7 public systems serving this county reported EPA UCMR 5 results; 2 had a PFOA or PFOS sample at or above 4.0 ng/L.

County figures describe where the lab is, not the lab. Sources: USGS 2015 water use and 2017 arsenic estimates, EPA radon zones, Census ACS table B25034 (2020–2024), EPA UCMR 5 (2023–2026); details and links on the sources page.

Before you send a sample

Call the lab to confirm it's currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Bacteria samples have short holding times. Status can change between list updates. To check a status, contact the Texas certification program.

Is this your lab?

Labs can ask for corrections through the agency that publishes their state list. Homeowner service, prices and turnaround above come only from the lab’s own website. To ask us to correct or remove this listing, write to us (how we handle listings).