If you get cold when you sleep, putting hot water in a Nalgene can be a great way to keep your sleeping bag nice and toasty.

But is it safe to do?

In this article I'm going to break down some myths and separate fact from fiction to answer some of the most frequently asked questions about this, like:

  • Is this safe to do?
  • Will it ruin your water bottle?
  • Will it leech chemicals out of the plastic?
  • How much heat does it actually provide?
  • Can you use a bladder to hold the boiling water?

Is It Safe To Put Boiling Water In A Nalgene?

Yes, it is totally safe to put boiling water in a Nalgene water bottle.

Nalgene is actually a type of plastic but most people know it as this iconic looking water bottle.

In the mid 2000's, there was some concern over BPA in all sorts of different plastics, including Nalgene water bottles.

Several outdoor gear stores, including REI, pulled these Nalgene water bottles off their shelves and replaced them with BPA-Free water bottles.

Since there isn't any BPA in these water bottles now, there' s no risk of chemicals leeching out and getting in your drinking water.

So yes, it's safe to put boiling water in a Nalgene.

Will This Ruin Your Nalgene?

Not all plastic can handle boiling water. 

For example, if you try to make  a dehydrated meal like a Mountain House in a regular zip lock bag, you're gonna have a bad time. It will melt and your food and boiling water will spill everywhere.

Luckily, Nalgene's are extremely durable and can handle boiling water without warping or distorting at all. 

There's no risk of 'breaking' your Nalgene from dumping boiling water in it.

Will Boiling Water Release Chemicals from the Plastic?

I already addressed BPA leaking out in the first section (not an issue now that these water bottles are BPA free), but what about other chemicals?

There isn't any evidence that putting boiling water in a Nalgene will cause any harmful chemicals to leech out.

That being said, I wouldn't drink that water in the morning. 

Dump out your boiling water in the morning and replace it with fresh water before you drink it.

Will This Actually Keep Me Warm?


If you're a cold sleeper, putting a Nalgene with boiling water in a sock and throwing it in by your feet is a great way to stay warm at night.

The sock part is important!

Boiling water is hot (duh, 212 degrees Fahreneheit). If you just throw the water bottle in a sleeping bag with your body, you're probably going to get burned.

Cover it with a shirt or sock to avoid direct contact with your skin and you'll be OK.

Can I Put Boiling Water In A Hydration Bladder?

No. This isn't a good idea.

Hydration bladders are made of a softer plastic (LDPE vs HDPE, low density vs high density) which means they aren't as strong or durable as a Nalgene. 

In addition to warping your bladder and possibly causing it to fail, the hydration bladder could leech chemicals.

There hasn't been anywhere near as much research done on how hydration bladders react to boiling water when you compare them to Nalgenes which ahve been studied extensively.

Sounds Cool. How Much Do Nalgene's Cost?

Nalgene's are super affordable. I'd recommend picking them up during REI Garage Sales if possible or just hop over to Amazon and grab one.