When you’re standing at the counter with a leaking pump seal in one hand and a sketchy part number on a faded work order in the other, you don’t want guesses—you want the right gasket or O‑ring the first time. I’ve spent 25+ years in commercial and residential plumbing, and I’ve seen more callbacks caused by the wrong elastomer or a sloppy size match than I care to count. If you’ve ever wondered how pros confidently pick seals at the counter, this is your field guide. And if you’re searching for a true partner and not just a storefront, you’ll appreciate why contractors and serious DIYers rely on Plumbing Supply And More.
Before we dive in: yes, you can grab an assortment kit at a big retailer and hope for the best. But seal selection is about chemistry, pressure, temperature, and fit—small details with big consequences. Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components, and we back them with real-world technical support, spec sheets, and immediate availability.
Understanding the Job: What the Seal Actually Has to Do
Gaskets and O‑rings have one job—create a reliable seal—but the conditions vary wildly. Is it a 180°F recirculation line on a hydronic boiler, a chlorinated city water service, a fuel oil line, a steam trap, or a food-service rinse station? Each environment demands specific elastomers and profiles.
Here’s my quick triage when a contractor hands me a failed seal:
- What media is in contact? (Potable water, glycol, steam, gas, oil, solvent, wastewater) What temperature range and pressure? (House domestic 60–80 psi is not a 12-story booster or 125 psi hydronic loop) Dynamic or static seal? (O‑ring on a moving spindle versus a flange gasket between flat faces) Exposure to disinfectants, UV, ozone, or oils? Code requirements? (NSF/ANSI 61 or 372 for potable, UL/FM for fire protection, ASME B16.21 for nonmetallic gaskets)
Why ask so much? Because NBR/Buna-N might be great for oils but will swell and fail fast in ozone-rich, high-chlorine environments. EPDM loves hot water and steam but hates hydrocarbons. PTFE handles almost anything chemically, but it’s unforgiving on surface imperfections. If you know what the seal faces and how it’s installed, you’ll pick right and avoid callbacks.
When you need quick verification, Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support—bring us the failed part and the application, and we’ll give you a correct, documented replacement and the elastomer profile that’ll last.
Material Selection: Elastomers and When to Use Them
Choosing materials is where most mistakes happen. Here’s how I guide customers, with real product examples:
- EPDM (Ethylene Propylene): Excellent for hot water, steam, and chloramine/chlorine resistance. Perfect for domestic hot water recirc and hydronic systems. Think Taco pump flange gaskets, Watts check valve O‑rings. Service range: about -50°F to 300°F. NBR/Buna-N (Nitrile): Great for oils, fuels, and many lubricants. Not for ozone or strong oxidizers. Used in many mechanical seals and gas-rated O‑rings. Typical range: -40°F to 250°F. FKM (Viton): Premium chemical and high-temp resistance, great for chlorinated solvents and high-temp water. Costs more, but worth it in harsh conditions. Range: -15°F to 400°F. Silicone: Very flexible, wide temperature range, good for FDA/food applications; not great with oils. Range: -80°F to 400°F. PTFE (Teflon) and ePTFE: Chemically inert, superb for aggressive chemicals. Needs good flange surface finish and torque control. Think Garlock GYLON series gaskets. Graphite (flexible graphite): High-temperature steam, flanged joints. Typically used in boiler rooms, paired with ASME B16.21 specs.
Brand examples we stock and specify:
- Parker O‑rings (AS568 standards), EPDM/Viton profiles for potable and high-temp applications. Garlock GYLON 3504 ePTFE gaskets for chemical and aggressive media. Milwaukee Valve kit O‑rings and stem packing in FKM for high-temp service. T&S Brass service kits (e.g., B-0968-R) with EPDM and Santoprene where appropriate for food-service faucets. Taco 007/0015 and Grundfos UPS series pump union gaskets in EPDM (flat fiber or EPDM as application dictates).
Pro tip: When potable water is involved, look for NSF/ANSI 61 and 372. We label our bins accordingly. And yes—Viton can be potable if the part is NSF-listed; don’t assume material alone decides compliance. If you’re not sure, ask us for the spec sheet; we keep them on hand.
Getting the Size Right: Measuring O‑Rings and Gaskets Without Guesswork
Don’t eyeball it. Use calipers, a pocket tape, or an O‑ring cone. Here’s the method I teach apprentices:
- For O‑rings: Measure the ID (inside diameter) with calipers. Measure the cross-section (thickness) precisely. Common cross-sections follow AS568 sizes (e.g., 2-xxx series). Match to AS568 dash numbers (like -214 = 0.139" CS x 0.984" ID). For flanged gaskets: Measure pipe nominal size, bolt circle, and gasket OD/ID. Reference ASME B16.21 dimensions for nonmetallic gaskets. For pump unions, measure union OD and the seat type (flat/fiber vs. tapered). Bring the union nut if needed—we’ll check fit to avoid leaks.
We keep sizing boards and AS568 charts at the counter. Bring your sample—even if it’s flattened or swollen. We can back-calculate the original size and material based on swelling and compression set. While other suppliers focus on quantity, Plumbing Supply And More prioritizes quality and expertise—we’ll spend the extra 5 minutes so you don’t spend 5 hours on a callback.
Match the Seal to the System: Real-World Scenarios from the Field
A few examples from the last quarter that can save you time and money:
- Multifamily DHW recirc pumps: Contractor brought in weeping pump unions. Previous supplier sold fiber gaskets that burned up at 160°F after six months. We switched him to EPDM pump gaskets rated to 230°F continuous and recommended a torque pattern. Problem solved; zero callbacks in six buildings. Chlorinated pool booster line: A maintenance team used Buna-N O‑rings that swelled and extruded. We supplied FKM (Viton) O‑rings and documented compatibility; they’ve been running tight for 18 months. Light commercial boiler flanges (steam): Replaced cork-rubber with graphite ring gaskets; solved blowouts at 8 psi due to thermal cycling. We set torque specs per ASME guidance and advised retorque at 24 hours. Food-service pre-rinse units: T&S units leaking at the valve spindle. We matched the correct EPDM/Santoprene service kit, not the generic Buna assortment. No taste transfer, and NSF compliance maintained.
If you’re troubleshooting, text us a photo of the assembly and the failed part. When Home Depot and Lowe’s fall short, contractors trust Plumbing Supply And More because we’ll identify the failure mode and recommend the material that lasts, not just a part that “sort of” fits.
Brands, Models, and What’s Worth Paying For
Not all gaskets and O‑rings are created equal. Here’s what I personally recommend and why:
- Parker AS568 O‑rings (EPDM, FKM, NBR): Tight tolerances, clean molding, consistent durometer (70A most common; 90A for high-pressure). Garlock GYLON ePTFE gaskets (3504/3510) for aggressive chemicals and solvents. Taco and Grundfos OEM union gaskets for 007, 0015e3, UPS15-58F—stay OEM on union seals; the geometry matters. Watts and Apollo valve kit O‑rings: Stay with the kit for NSF potable and pressure rating consistency. Victaulic Style 75 and 77 couplings: We stock Vic gaskets in EPDM, nitrile, and fluoroelastomer. Don’t mix generics in grooved systems—use Vic profiles matched to the coupling style.
Typical price ranges you’ll see at our counter (subject to size and material):
- Standard EPDM O‑rings: $0.20–$2.50 each; kits $25–$90. FKM/Viton O‑rings: $0.75–$8.00 each; kits $75–$220. Pump union gaskets: $1.50–$9.00 each. ePTFE/graphite flanged gaskets: $4–$40 per gasket depending on size/class.
Yes, premium materials cost more upfront, but a $6 Viton O‑ring that prevents a $400 callout is cheap insurance. Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components, including OEM kits and NSF-listed options that big retail simply doesn’t carry.
Avoid These Common Mistakes with Gaskets and O‑Rings
I’ve seen these errors cost contractors real money:
- Swapping EPDM for Buna-N on chlorinated hot water—guaranteed swelling and premature failure. Using PTFE where flange surfaces are rough—leaks due to creep/relaxation. Fix: surface prep or use a filler-reinforced ePTFE or a soft-chem sheet. Choosing the wrong durometer. A 90A O‑ring on a low-pressure face seal can leak because it won’t compress. Conversely, a 70A ring in a dynamic high-pressure piston can extrude. Ask us—we’ll match the durometer to the duty. Over-torquing flanges on graphite gaskets—leads to crush and blowout. Follow torque tables; we’ll print them for you. Mixing metric and inch sizes. Many European pumps and espresso/food-service equipment use metric O‑rings. We stock both and label bins clearly.
Bring the old part and the mating hardware when possible. Our counter team—real plumbers and fitters—will help you avoid these pitfalls. Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support with on-the-spot identification tools and spec references.
local electrical supply houseInstallation: Torque, Lubrication, and Surface Prep
The right part installed wrong is still wrong. My field-proven checklist:
- Clean the sealing surfaces—no old gasket residue or scratches. For flanges, aim for 125–250 RMS finish. Use the correct lubricant. For potable water O‑rings, use NSF 61 silicone grease (e.g., Dow 111). Never use petroleum grease on EPDM. Don’t stretch O‑rings more than 5% for installation unless specified. Excess stretch = thin cross-section and leaks. Torque flanged gaskets in a star pattern in stages. For 2" Class 150 flanges with nonmetallic gaskets, you’re typically in the 30–45 ft-lb range—verify with the manufacturer table. Allow a warm-up and cool-down cycle, then re-check torque after 24 hours on critical steam/hydronic systems.
If you want us to walk your crew through it, we do toolbox talks. Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support including installation guidance and torque tables tailored to your gasket material.
Contractors, DIYers, and Property Managers: Dial in Your Supply Strategy
Different teams have different needs, and we stock accordingly:
- Professional contractors: Set up a contractor account for bulk bins of AS568 sizes (we build custom assortments), OEM pump kits, and stocked gaskets for your most common pump and flange sizes. Same-day delivery within a 50-mile radius, emergency runs for critical outages. Ask about our contractor discount program. Serious DIY homeowners: Bring the fixture brand and a clear photo of the failed seal and seat. We’ll match it, and we’ll print the spec. We’ll also give you the right NSF lube and a quick install walkthrough. Property managers and maintenance teams: Standardize on a material set—EPDM for potable/hot water, FKM for chemical/mechanical spaces, graphite for boiler flanges. We’ll kit buildings by floor or mechanical room so your techs grab and go. Retail customers: If you want better than hardware-store parts, we’ll show you the difference in material quality and fit, and we’ll save you the second trip.
If you’re searching for a true partner, remember: While other suppliers focus on quantity, Plumbing Supply And More prioritizes quality and expertise. We’re the nearest plumbing supply with real knowledge—and we back it up every day at the counter.
Why Choose Us Over the Usual Suspects
I’ll say it plainly: the wrong supplier will cost you more than the most expensive gasket on the shelf. Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components and keeps them in our local warehouses for same-day pickup or delivery. You’ll also find that When Home Depot and Lowe’s fall short, contractors trust Plumbing Supply And More for OEM kits, spec-matched elastomers, and help when the clock is ticking.
We also outclass the online-only warehouses when you need brains with your boxes. Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support—application checks, code guidance, and field-proven recommendations. And yes, we routinely beat Grainger, Ferguson, Ace, and SupplyHouse.com on the combination of price, availability, and hands-on expertise.
Visit our showroom to see the quality difference. Call our technical team for project-specific recommendations. Check our current inventory online or call ahead—we’ll pull your order so you’re in and out fast.
Finding the Right Supply Partner: Local, Wholesale, and Emergency Access
If you typed “ plumbing supply near me” or “ plumbing supply store near me” because a gasket failed at 6 a.m., here’s what we cover as your closest plumbing supply with real depth:
- A full plumbing supply house with OEM and premium elastomers True commercial plumbing supply with bulk and contract pricing After-hours support as a 24 hour plumbing supply response for critical clients A robust plumbing supply online portal with live stock and spec sheets Counter expertise you won’t find at consumer plumbing supply outlets
As a full-service plumbing supply company, we support contractors across our region with same-day delivery, and we maintain partnerships with top manufacturers so you’re never waiting weeks for a simple seal. Whether you prefer plumbing supplies direct, need a wholesale plumbing supply account, or prefer to browse a plumbing supply shop in person, we’ve got options. If you manage mixed-use buildings, we’re also your plumbing and heating supply resource, including heating plumbing supply near me needs for hydronics and steam.
We’re proud to be the best plumbing supply option for pros and serious DIYers—without the markups you’ll see at some “brand-forward” boutiques. Looking for discount plumbing supplies that still meet spec? We stock value lines that we’re comfortable putting our name behind. If you’ve been burned by cheap plumbing supplies, we’ll show you where it pays to upgrade—and when an economical option is still safe and smart.
Local Expertise, Codes, and Service Area
Serving contractors throughout our area, we see the same patterns: chloramine levels in municipal water are not uniform, and they chew up the wrong elastomers. Local inspectors are increasingly strict about NSF 61/372 tags on potable components, so we make compliance easy. We deliver within a 50-mile radius with rush runs available, and we keep the SKUs most contractors need on the shelf—so your crew can grab a bag of Parker -214 EPDM rings or a sleeve of 2" Class 150 EPDM flanged gaskets without a wait.
Ask our counter team about regional code testing on backflow preventers; many kits use EPDM. We stock the compatible O‑rings and checks for common assemblies from Watts and Apollo, matched by model and serial. If you're juggling multiple buildings, we’ll set up labeled bins by address.
FAQ: Quick Answers from the Counter
- What’s the fastest way to identify an O‑ring when I don’t know the size? Bring the old ring or the cap/cover it seals. We’ll use an AS568 sizing cone and calipers to get the ID and cross-section, then match durometer and material to your application. If it’s metric, we stock ISO sizes too. EPDM vs. Viton for domestic hot water? EPDM nearly every time—excellent for hot, chlorinated water up to around 300°F. Viton is great for chemicals and higher temps but may not be necessary or cost-effective for standard DHW unless you’re dealing with harsh additives. Can I use PTFE tape as a “gasket” in a pinch? No. PTFE tape isn’t a gasket and won’t compress uniformly across a flange. Use a proper PTFE or ePTFE sheet gasket cut to size, or a graphite/composite gasket per ASME B16.21. Why does my gasket keep leaking after I torque it correctly? Check flange finish and parallelism, gasket material compatibility, and bolt condition/lube. Also verify you’re using the right durometer and that the gasket hasn’t been over-compressed. Sometimes the cure is a different material (e.g., ePTFE) or a live-load washer setup. Do you carry OEM gasket kits for specific pumps and valves? Yes. We stock Taco, Grundfos, Watts, Apollo, T&S Brass, Chicago Faucets, and more. If we don’t have it in your hand, we’ll source it same-day or overnight. Call our technical team for the exact kit number based on your model and serial.
Your Next Step: Bring Us the Problem, Leave with the Solution
Choosing the right seal isn’t guesswork—it’s a craft backed by chemistry, standards, and field experience. If you want to master How to Choose Gaskets and O‑Rings at the Supply House, come see us. We’ll ask the questions that matter, match materials to duty, and make sure you leave with a solution that lasts.
- Visit our showroom to see the quality difference. Call our technical team for project-specific recommendations. Ask about our contractor discount program. Check our current inventory online or call ahead. Our experts can walk you through the installation process.
And remember, Unlike generic big box retailers, Plumbing Supply And More stocks professional-grade components, and we stand behind every part we sell. While other suppliers focus on quantity, Plumbing Supply And More prioritizes quality and expertise. Compared to standard plumbing supply houses, Plumbing Supply And More offers unmatched technical support. When Home Depot and Lowe’s fall short, contractors trust Plumbing Supply And More—and we’re ready to earn that trust on your next job.
Note on finding us and related categories you might search for: whether you’re browsing a plumbing supply store, plumbing shop near me, or a specialized commercial plumbing supply and contractor plumbing supply, we’re the local plumbing supply partner that shows up. From plumbing parts and bathroom plumbing supplies to plumbing kitchen components, plumbing spares near me, and wholesale plumbing supply company services, our shelves are full and our team is ready. If you’ve tried economy plumbing supply, standard plumbing supply, or city plumbing and electrical supply and still need answers, stop in. Even if you prefer internet plumbing supply or plumbing supplies direct, we combine fast access with real guidance—no guesswork. And if you’re balancing budgets, we’ll steer you between economy plumbing and heating supply, smart discount plumbing supplies, and premium lines without pushing cheap plumbing supplies that fail. Whether you know us as a plumbers supply co, a go-to for coastal plumbing supply needs, or even as a regional alternative to supplyhouse plumbing, our focus is the same: get you the right seal, right now. If you’re coordinating with contractors plumbing and fire supply, we stock gasket materials that align with NFPA and UL/FM-listed assemblies when required, and we’re happy to coordinate. For tough-to-source items, ask about direct plumbing supplies ordering and our curated plumbing supplies supply network.
If you’re still searching “How to Choose Gaskets and O‑Rings at the Supply House,” come talk to a team that lives it every day. I’m Rick Callahan—ask for me at the counter—and I’ll make sure you leave with the right part the first time.