Q. I really enjoy taking long baths that use some lavender oils, etc., to relax on weekends and after work. How often (if at all) can we take baths in an environmentally friendly way, and are there certain products to use that are better than others?

Conscious Bather
Berlin

A. Dearest Conscious Bather,

Well, better a 45-minute bath than a 45-minute shower. Unfortunately, though, lavender-scented soaks fall into the category of Delightfully Luxurious Things We Probably Shouldn’t Have Every Day (right up there next to cupcakes). Unless you’re content with a mere foot bath, showers almost always beat out baths in terms of water use.

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The numbers I’m about to hit you with are averages, so things may vary a bit based on the size of your tub and the style of your showerhead. But according to the United States Geological Survey, the typical bathtub holds about 36 gallons of water. Presumably, you’re only partially filling it (if not, I think I know why your bath mat is sprouting mold), so the typical bath is probably more in the 20- to 30-gallon range.

If you take long showers with a standard 2.5-gallon-per-minute (gsm) showerhead, you won’t be too far off that number: Eight to 12 minutes under the flow will fill your tub to the 20- to 30-gallon mark. But if you’ve switched to a WaterSense showerhead — and I do hope you have — with a 2 gsm rating, you’d have to scrub-a-dub for 10 to 15 minutes for a bath to win out. With an even water-friendlier 1.5-gsm model, it’d be 13 to 20 minutes. You’d definitely be pruney by then.

Now, Conscious Bather, those are some long showers. If you’re taking a more reasonable 5-minute shower with a 2-gsm showerhead, you’d use just 10 gallons — even fewer if you go military style and shut off the nozzle while you lather up. Put another way: It’s easy to take steps toward a water-miserly shower, but a 20-gallon bath will always glug 20 gallons. You can experiment with filling the tub less and less, I suppose, but at a certain level you begin to lose the point of a bath in the first place.

This does not mean I think you should swear off your favorite stress reliever forever. Flowery hot-water soaks are one of life’s little pleasures. But I do advise you to be frugal with them — think “special treat,” not “daily hygiene.” One way to tackle this might be to make each bath a reward for saving water elsewhere (a water offset, so to speak). Let’s say your baths use 25 gallons and you’re accustomed to those 5-minute, 10-gallon showers I noted above: You’d need to save 15 extra gallons to justify that next bath. You might do that by whittling your next 4 showers down to 3 minutes each. Or skipping two showers one week. Bigger gestures like installing WaterSense faucets and toilets or a high-efficiency washing machine would buy you a few more indulgences, too.

And what about reusing your bathwater, Conscious Bather? It’s a classic conservation move: collecting the wastewater (gray water) from baths, showers, and laundry for another use, such as irrigating your plants or manually flushing the toilet. Since your baths would be infrequent, you could make do transferring the water with a bucket, or you could rig up a hose siphoning system.

That brings us to your final question: What about the bath products? If you’re rocking any sort of gray water tactics on your yard (and even if you’re not), nontoxic is the name of the game. You can find a few suggestions here, and, as always, the Environmental Working Group’s Skin Deep database is an excellent resource for checking out the toxicity of a specific product’s ingredients (this one could be a winner for you). And if you’re not sure if your bubble bath is safe for reuse outdoors, here’s one more tip: Handwash your delicates in the tub after you’ve handwashed yourself!

Any of these steps will help you live up to your pseudonym. And what’s more, they’ll probably make each precious bath all the more enjoyable, too.

Bubbily,
Umbra