My water heater sits on a concrete slab floor in my utility room next to a wall with a bathtub drain, and a few feet over from my washing machine drain. When I replace the heater I would like to install a water heater pan and have it connected to the tub drain (I haven't yet consulted a plumber about this--I assume it would be possible).

The issue I see is that if the water heater pan is sitting on the floor then the drain will--at best--be level. Will the drain is effective in this scenario? Would the heater need to be raised so that the drain could better be gravity fed?Would another option be altogether better?

3 Answers 3


Installing a pan under a water heater is always a good idea. As a contractor, I have responded to many leaking tanks over the years and a drained pan would have made the situation a lot cheaper and easier for the customer. the leak is one thing, but the collateral damage is another. If you have clearance above the water heater, you could raise the level with a few concrete patio blocks so it could drain down to the shower drain. If you have a sump hole in your floor, that is a good option. If using a shower drain, this assumes you can tap into it above the trap. Plumbing it into the washer drain might be tricky because you would need a pump to lift the water to the drain inlet. Not seeing your set up makes it difficult to say for sure. There are also simple alarms that sense water and sound an alarm etc. This would give you a heads up before the pan over flows and floods the floor.

  • Thanks for the feedback. So to make sure I understand, a gravity fed drain does require the pan to be above the drain (and to drain above the trap, to avoid sewer gas). If the drain is above or level to the pan then a pump might be an option, but more complicated and expensive.
    – STW
    Mar 13, 2014 at 17:54
  • yes, I think you got it. Mar 13, 2014 at 21:15
  • I've heard that the pans will fill up in a couple of minutes; the alarm might work if you happen to be home. Simplisafe has water sensors to trigger an alarm and phone call, but without a pump, I don't think the pan would be of much use while you're out. Apr 12, 2016 at 15:01

Placing a Drain Pan under your hot water heater is a smart idea. Elevating the hot water heater will offer better draw especially if you were to have a large leak. Most customer's we work with will use a fitting in the hole that will connect with some type of tube that will drain through the floor or if outside, drain down away from structure. We offer Drain Pans and bulk head fittings so that you could connect to the tub drain.


Any drain pan gravity drained into a sewer line runs the risk of a back up which can overflow the pan even when the water heater is not the problem. Use a pump.

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