Quick Answer: Most tankless water heaters don’t legally require a drain pan — the IRC/IPC pan rule was written for 40-80 gallon storage tanks, not the small amount of water held in a tankless heat exchanger. A pan is required (or simply worth adding) whenever the unit is installed over finished living space, in an attic, or anywhere a leak could damage the structure below. If you need one, the Oatey 34061 (about $20, plastic, 20”) is the cheapest option that fits most units, while the Camco 11470 (about $43, plastic, purpose-built for wall-mounted tankless units) is the closest match to how a tankless heater actually mounts.
Tank water heaters get a dedicated code section because a burst 50-gallon tank can dump 50 gallons onto a floor in minutes. A tankless unit’s heat exchanger holds closer to a quart, so most inspectors don’t apply the same pan requirement — but “usually exempt” isn’t “always exempt,” and a leaking supply line, condensate line, or fitting above a finished ceiling can still do real damage even from a small unit. This roundup covers when you actually need a pan and which one fits.
When code actually requires a pan
IRC Section P2801.6 and IPC 504.7 require a drain pan whenever a water heater is installed in a location where a leak would damage the structure or finish materials below it — over a finished ceiling, in a closet above living space, or in an attic, regardless of whether the unit is tank or tankless. A garage floor, unfinished basement, or mechanical room with a floor drain typically doesn’t trigger the requirement, since there’s nowhere for a leak to cause secondary damage. Where a pan is required, it must be at least 1.5 inches deep and drain through an indirect waste pipe of at least 3/4 inch to an approved point — a pan sitting there with no drain line doesn’t meet code. Check your local jurisdiction’s amendments before skipping a pan on a borderline install; some cities require one for any interior tankless unit regardless of the IRC baseline.
Our top picks at a glance
| Pan | Material | Size | Best For | Price |
|---|---|---|---|---|
| Oatey 34061 | Plastic | 20" dia., 1"-1.5" PVC adaptor | Cheapest option, unfinished spaces | ~$20 |
| Eastman 60079 | Aluminum | 24" ID / 26" OD | Gas units, best value in aluminum | ~$25-$28 |
| Camco 11470 | Plastic | 20.5" W x 13" D, PVC fitting | Purpose-built for wall-mount tankless | ~$40-$44 |
| Camco 11430 | Aluminum | 20.5" W x 13" D, PVC fitting | Attic/gas installs, longest-lasting | ~$60-$90 |
1. Oatey 34061 — Cheapest Option
Oatey 34061 Plastic Water Heater Pan
- Not tankless-specific — this is the standard round pan sold for tank heaters — but at 20" across it fits underneath most wall-mounted tankless units with room to spare, since a tankless unit's footprint is smaller than a tank's base.
- The PVC adaptor threads to standard 1" or 1.5" drain line, meeting the IRC/IPC 3/4"-minimum indirect-waste requirement with room to spare.
- Round shape and generic branding means it looks slightly out of place mounted flush to a wall-hung unit, but for an unfinished basement or garage install where appearance doesn't matter, it's the lowest-cost way to meet code.
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This is the pick if you just need to satisfy an inspector or add cheap insurance and don’t care about a purpose-built fit — it’s a generic tank-heater pan, but it’s deep enough and drains correctly.
2. Eastman 60079 — Best Value in Aluminum
Eastman 60079 Aluminum Water Heater Pan
- Aluminum construction won't crack from the heat cycling that a plastic pan can see when it sits near a gas tankless unit's exhaust vent — a real consideration for closet or attic installs where ambient heat runs higher.
- At 24"/26", it's wider than most tankless footprints, so it also works as a universal pan if you're not sure of your exact model's dimensions.
- Priced only slightly above the plastic Oatey option, making this the better default any time the unit is gas-fired rather than electric.
If your unit is gas-fired, this is the sensible upgrade over plastic for barely more money — aluminum tolerates the heat near a gas unit’s vent connection better over years of service.
3. Camco 11470 — Purpose-Built for Wall-Mount Tankless
Camco 11470 Tankless Water Heater Drain Pan
- Unlike the Oatey and Eastman pans above (both designed for round tank heaters), Camco's 11470 is a rectangular pan shaped to sit flush under a wall-mounted tankless unit's actual footprint.
- Meets the IRC/IPC 1.5" minimum depth exactly, with the PVC fitting sized for standard 1" or 1.5" indirect waste line.
- Works for gas or electric units per Camco's spec — the plastic body is the only tradeoff versus the aluminum 11430 below if the pan will sit close to a gas exhaust.
This is the pick if you want a pan that actually looks and fits like it belongs under a tankless unit rather than a generic tank-heater pan repurposed for the job.
4. Camco 11430 — Best for Attic and Gas Installs
Camco 11430 Aluminum Tankless Water Heater Drain Pan
- Same purpose-built rectangular shape as the 11470, but in aluminum — the pick if the unit is gas-fired and mounted somewhere hard to inspect regularly, like an attic or a closet you don't open often.
- Aluminum won't rust, crack, or corrode over years of exposure to condensate or ambient heat the way a plastic pan eventually can.
- Costs roughly double the plastic 11470; the premium buys longevity that matters more in a location you can't easily monitor than in a garage you walk past daily.
If the unit is going in an attic, a closet above finished space, or anywhere else you won’t spot a slow leak quickly, this is the pick worth the extra cost — it’s the same fit as the 11470 in a material built to last in a location you’re not checking every week.
How to choose
- You just need to satisfy an inspector or add cheap insurance: the Oatey 34061 at ~$20.
- Your unit is gas-fired and budget matters: the Eastman 60079, aluminum for barely more than plastic.
- You want a pan shaped for how a tankless unit actually mounts: the Camco 11470.
- The unit is in an attic, closet, or anywhere hard to check regularly: the Camco 11430, aluminum in the tankless-specific shape.
- You’re not sure if you need a pan at all: check whether the install is over finished space or in an attic — if it’s a garage, unfinished basement, or mechanical room with a floor drain, most jurisdictions don’t require one, though it remains cheap insurance either way.
The bottom line
A drain pan is a $20-$90 purchase that most tankless installs don’t legally require — the IRC/IPC pan rule (1.5” minimum depth, 3/4” indirect waste line) exists for 40-80 gallon tank heaters, and a tankless unit’s small heat exchanger doesn’t trigger it in most garage, basement, or mechanical-room installs. It is required, and worth adding regardless of code, any time the unit sits over finished living space or in an attic. For most owners, the Oatey 34061 or Eastman 60079 cover it cheaply; the Camco 11470/11430 pair fits the actual tankless footprint if you want a purpose-built look. For the rest of a compliant install, see our tankless water heater installation guide and venting guide.