Schedule 40 and Schedule 80 PVC share the same outside diameter at every nominal size, which means they use the same fittings and the same tools. What separates them is wall thickness — and that one difference decides pressure rating, flow, chemical service, and whether an inspector signs off. Here is how the two grades split up across Los Angeles plumbing, irrigation, drainage, and electrical work.
The short answer for most LA work
Schedule 40 covers the overwhelming majority of residential and light commercial jobs: drain, waste and vent lines, irrigation, pool and equipment plumbing, sprinkler mains, and electrical conduit. Schedule 80 is the heavier-wall grade, identifiable by its grey color against Schedule 40's white, and it belongs where pressure is high, where the pipe is physically exposed to impact, or where the service is industrial or chemical. On a typical house, ADU, or tenant improvement in the basin, Schedule 40 is the correct specification and Schedule 80 is over-building.
The thicker wall in Schedule 80 buys pressure capacity and impact resistance, but it costs you interior diameter. At the same nominal size a Schedule 80 pipe flows less than a Schedule 40 pipe, which matters on a long irrigation run or a drain line where you are already at the edge of the sizing.
| Grade |
Wall |
Color |
Typical Use |
| Schedule 40 |
Standard |
White |
DWV, irrigation, conduit |
| Schedule 80 |
Thicker |
Grey |
High pressure, exposed runs |
| SDR pressure |
Ratio based |
White |
Buried water lines |
What Schedule 40 actually covers
Schedule 40 is dual-marked, and that is the detail most people miss. The same pipe is rated for both DWV and pressure service — what changes is the fittings. DWV assemblies use gradual-sweep fittings that keep solids moving; pressure assemblies use sharply angled fittings designed for the hydraulics. Buying the right pipe and the wrong fitting family is a common and entirely avoidable mistake.
Our 2 in. x 10 ft. Schedule 40 solid core pipe is the dual-rated workhorse, with high tensile and impact strength, better sound dampening than foam-core PVC or ABS, and a maximum operating temperature of 140°F. It meets ASTM D 1784, ASTM D 2466, and NSF 14 and 83. For drainage sizing, the 4 in. x 10 ft. Schedule 40 DWV pipe is the standard building drain and sewer lateral size.
That 140°F ceiling is the constraint worth remembering. PVC is not a hot water material. Hot supply lines are copper or PEX — our guide to copper pipe types M, L and K covers that side of the system, and the ABS pipe guide covers the black-pipe alternative that many LA jurisdictions accept for DWV.
SDR pressure pipe is a third category
Alongside the schedules there is SDR pipe, rated by standard dimension ratio rather than schedule. Our 1 in. x 10 ft. PR-200 pressure pipe is part of that family — designed for pressure applications up to 140°F, resistant to a wide range of chemicals, and meeting ASTM D 1784, ASTM D 2241, and NSF 14 and 61. The useful property of SDR pipe is that the pressure rating holds constant across diameters, which makes sizing a buried irrigation or service line straightforward.
For buried irrigation and utility work the store also carries a full underground-rated fitting family — couplings, tees, elbows, caps and adapters in the PVC Pipes & Fittings collection — so a trench can be built out of one compatible system rather than assembled from whatever matches.
Where Schedule 80 earns its place
Three situations justify the heavier wall. The first is genuinely high working pressure — pump discharge, filtration loops, commercial equipment skids. The second is mechanical exposure: a riser standing proud in a yard, a run across a parking structure, anything a vehicle or a landscaper's equipment can hit. The third is chemical or industrial service, where the thicker wall provides margin against attack from the inside.
Pool and spa equipment is where LA homeowners meet Schedule 80 most often. Many pump and filter manufacturers specify grey pipe at the equipment pad, both for the pressure and because the run is exposed to sun and physical contact. UV is the honest weakness of all PVC — unpainted white pipe left in Southern California sun will chalk and embrittle over a few seasons regardless of schedule. Any exposed run should be painted with a compatible coating or sleeved, and that applies to Schedule 40 and 80 alike.
We stock Schedule 40 pipe, fittings and conduit in the common sizes for pickup and delivery across the LA basin. If your plans call for Schedule 80, send us the sizes and lengths and we will source it for the job.
Electrical conduit is its own conversation
PVC electrical conduit is a different product from plumbing pipe even though the schedule naming overlaps. Conduit is UL and ETL listed, rated for use with 90°C conductors, manufactured to NEMA TC2, and it is non-conductive and moisture resistant — properties that have nothing to do with carrying water. Our 3/4 in. x 10 ft. Schedule 40 PVC conduit is the standard size for residential branch circuits, with 1 in. through 3 in. available for feeders and service runs.
Never substitute plumbing pipe for conduit or the reverse. They are listed for different purposes, and an inspector will spot white DWV pipe used as a raceway immediately. For the full picture on raceway selection in LA — where EMT is expected, where PVC is allowed, and how the permit conversation usually goes — see our guide to EMT vs PVC vs flexible conduit.
Joining it correctly
Both schedules join the same way: cut square, deburr, dry-fit, prime, cement, and give it a quarter turn as you seat it. The steps people skip are deburring and priming, and both show up later as leaks. A burr left inside the pipe catches debris in a drain and disturbs flow in a pressure line; skipping primer produces a joint that looks finished and fails under pressure test.
Cure time is not optional and it is temperature dependent. In an LA August a joint sets fast; on a damp winter morning in a coastal neighborhood it needs longer than the label's fastest figure. Pressure-test before you backfill a trench, not after — reopening a trench is the expensive part of the job.
Support and expansion matter on long runs. PVC moves with temperature more than metal does, and a rigidly clamped run baking in a Valley attic or crossing an exposed roof will find somewhere to relieve that stress. Strap the pipe at the intervals the code requires and let it move slightly rather than pinning it.
Choosing sizes for LA projects
Order by nominal size, and remember that nominal is not the measured dimension — this is the same catch that trips people cross-shopping copper against PVC. Size drainage by fixture units and the plumbing code rather than by what fits the existing hole, and size irrigation and pressure runs for the flow you need at the far end, allowing for friction loss over long horizontal distances.
For yard drainage and sewer laterals, the sewer and drain products — perforated and solid S&D pipe in 4 in. and 6 in. — sit in the same PVC Pipes & Fittings collection, and the broader Plumbing category covers valves and transitions. Plan your shut-offs while the trench is open; our guide to ball vs gate vs angle stop valves walks through which valve belongs where.
Frequently asked questions
Can I mix Schedule 40 and Schedule 80 in one system?
Yes. Both share the same outside diameter, so fittings interchange and a transition needs no adapter. Rate the system by its weakest component — a Schedule 40 section in a Schedule 80 run caps the whole line's pressure rating.
Why is Schedule 80 grey?
The color is an identification convention, not a performance property. Grey signals the heavier wall so an inspector or the next tradesperson can tell the grades apart at a glance, the same way copper tube is color-coded by type.
Can PVC carry hot water?
No. Both schedules are limited to about 140°F, which rules out domestic hot water supply. Use copper or PEX for hot lines.
Does PVC hold up outdoors in Southern California?
Not indefinitely when left unprotected. UV degrades PVC over time, so any exposed run should be painted with a compatible coating, sleeved, or buried. Buried and interior pipe is unaffected.
Do I need Schedule 80 for a pool equipment pad?
Check the equipment manufacturer's specification. Many call for Schedule 80 at the pump and filter for the pressure and the physical exposure, then allow Schedule 40 for the buried runs out to the pool.
