CrazyCap 2 UV Water Bottle Review

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We’re avid hikers and are always looking for reliable, lightweight water filtration solutions that we can pack in our backpacks and filter water on the go. We’re used to fiddly pump filters and straw filters, so the Crazy Cap just about blew our minds – it’s a stainless steel water bottle with a cap that purifies any water source at the tap of a button.

We used the CrazyCap to filter river water on our Colorado-based hikes and excursions, and here’s what we thought about its performance.

Important note: For this guide, we’ve tested and reviewed the CrazyCap. A new version of this, the CrazyCap Pro, has since been released. It has better stats, including the ability to filter water with a 20 mW LED UV light, and included hydration reminders. The general design and features of the newer model are otherwise the same, so the contents of this review still applies.

🧾 Overview of the CrazyCap Water Purifier

The CrazyCap is a stainless steel water bottle cap that purifies water at the touch of a button. There are two main buying options for this purifier:

  • On its own – The cap fits on cola-style bottles like S’Well, Chilly’s, and Mira bottles, which all have the same-sized bottle mouth, so you can use it with your own bottle if you prefer.
  • With an included bottle – You can buy the CrazyCap with a 500ml/17-ounce or 740ml water bottle in several different colors (this is what we personally did).

The CrazyCap Pro uses a 20 mW LED light, which is powerful enough to destroy bacteria, viruses, and other pathogens. The CrazyCap LYT is similar, but has a 10-12mW UVC LED, and is intended for when you “almost trust a water source, but aren’t quite sure”.

The CrazyCap bottle isn’t like most filtered water bottles. It doesn’t use a bulky filter that needs to be changed every couple of months, and you don’t have to drink through an awkward straw.

Instead, this stainless steel bottle uses UV technology to disinfect the water in the bottle – and all it takes is a couple of taps on the lid.

Crazycap purifier bottle

In our testing, the CrazyCap stood out for being lightweight and really easy to use. We were won over by its simplicity: we could simply fill our bottle with water, then purify it within 60 seconds by tapping the button on the lid. However, the CrazyCap couldn’t physically filter sediment and turbidity out of our water, and, in fact, turbid water could hinder the UV sterilization process, which meant we could only use it to purify clean, clear water sources.

👍 What We Like

  • Two style choices, including a less powerful LYT option and an ultra-powerful PRO version
  • Can buy with a bottle or use with your own compatible bottle
  • No need to sip on a straw or use any other manual purification method
  • Lightweight design
  • Targets bacteria and viruses
  • Super simple to use
  • Quick to charge & retains charge for a long time

👎 What We Don’t Like

  • Doesn’t physically filter water
  • Not compatible with all bottle styles
  • Can’t be used with turbid water
  • Doesn’t adapt to large bottles

💡 First Impressions

When we unboxed the CrazyCap, we noted that it was surprisingly small and lightweight. The bottle cap itself doesn’t look or feel much different from a conventional, non-UV bottle cap – it’s small enough to fit in the palm of our hand and weighs just over 3 ounces (with the charger). When screwed on the 500ml bottle, it weighs just over 12.5 ounces.

The box that was shipped to us contained the following items:

  • The CrazyCap bottle lid
  • The insulated stainless steel 500ml bottle
  • The portless charger
  • The user manual
Crazycap pro unboxing

To get started, we had to charge the bottle lid fully – and that was it! We were ready to fill and use the bottle without having to prime a filter or commit to an assembly or setup process. We also appreciated having just one bottle that we could refill, rather than having a stock of plastic water bottles weighing down our backpacks.

Design-wise, the CrazyCap is pretty unique from many of the other bottle water filters we’ve tested. The fact that everything needed for purification is concealed within the bottle lid is a major advantage from a portability and space-saving perspective. We were able to slot the bottle easily in our backpack side pocket, and we found that the bottle’s insulating abilities were great – it kept our water cold even during our hottest summer hikes.

Something important to note is that the CrazyCap can only fit on a certain water bottle style, known as the Cola-style bottle (think Chilly’s). Plus, it can’t actually be used without a bottle, so it might not be ideal if you’re packing superlight. We were personally comfortable taking the CrazyCap with us on our hikes, but we made sure it was charged fully in advance. We did not want to face a situation where the device had no charge and we had no other means of purifying our water.

As with all products sold by WAATR (the brand behind the CrazyCap), the CrazyCap is backed by a lifetime warranty against defects in materials and workmanship (NOT normal wear and tear or damage caused by accidents and improper use). The warranty entitles customers to a free replacement product throughout the 10-year warranty period (terms and conditions apply).

🧪 Our Testing

As we mentioned, to produce this Crazy Cap water bottle review, we tested the purifier ourselves on several hiking trips in Colorado.

There were a few specific performance factors that we wanted to test the CrazyCap bottle for, including its ability to improve our water quality, ease of setup and use, and treatment time.

We’ve discussed these points in detail below.

Our Water Quality

The CrazyCap uses a 20 mW LED light that scrambles the DNA of microorganisms, preventing them from reproducing. There are two modes: normal mode – tap twice – (which lasts 60 seconds and kills around 99.1% of microorganisms, and crazy mode – tap five times – (which lasts 90 seconds and kills 99.99999% of pathogens).

This water bottle purifier is not a filtration system, so it couldn’t remove the likes of chemicals, heavy metals, and particulates from our water. We also had to be careful to only use the bottle to treat clear water or filter murky water in a cloth handkerchief before adding it to the bottle, since turbidity and sediment can shield microorganisms and prevent the UV light rays from penetrating them.

The CrazyCap didn’t make a noticeable difference to our water quality, taste, or smell, and we didn’t expect it to, given that it only kills microorganisms (which can’t be seen, tasted, or smelled). This was a little disconcerting at first, since we had no way to test for certain that the purifier was actually purifying our water. We just had to trust that it was doing its job.

We haven’t been able to do a before-and-after water quality test with the CrazyCap, but it’s on our list, and we’ll update this review once we have.

A random added bonus of the CrazyCap is that it can also be used to sterilize laptops, phones, and other surfaces. We haven’t really used this feature much, but we did test the device on our phones. Again, there’s no real way of knowing that it’s worked, but it’s a novelty feature all the same.

Filling crazy cap bottle
Sterilize clear water from natural sources

Ease of Setup and Use

We don’t mind spending a few minutes setting up a water filter or purifier while we’re hiking, but a product always gets extra brownie points from us if it’s super quick and easy to set up and use.

There’s essentially no setup process for the CrazyCap – we just made sure the bottle cap was charged before we took it out on our hikes. Then, we could fill our bottle and tap the lid (we usually tapped it five times to activate the crazy mode purification to be on the safe side), purifying the water in a matter of seconds. The fact that there are no filters to prime or backwash, no fiddly components to connect, and no hand-pumping or pushing, makes it one of the most easy-to-use portable water purification systems on the market.

We liked that we could use this UV filter to purify water on the move – we didn’t have to drink directly from the water source as is the case with straw filters, and we didn’t have to stop to wait for water to filter before we could pack up our equipment and move on, as with pump and hanging gravity filters. That meant we could put less focus on the practicalities of purifying our water and spend more time enjoying our hikes.

The cap itself is super helpful in letting you know what you need to know. It glows blue while it’s purifying water, and red when it needs a charge.

We’ve used the CrazyCap a few times in our daily lives, too, considering we don’t have to do any assembly or wait for the water to filter. In the same amount of time it would take us to remove a water bottle from the fridge and open the lid, we could fill our CrazyCap bottle and tap the lid to purify it. However, despite its ease of use, we don’t think this product shines when it comes to purifying municipal water, which is already pathogen-free. We prefer to use a bottle filter that can physically remove chlorine, heavy metals, and other common city water contaminants in this case.

The CrazyCap isn’t the smallest portable filter we’ve tested because it needs to be used with a water bottle. But if you have room in your bag for a standard-size 500ml water bottle, you’ll have enough space for the CrazyCap. If you’d rather go bag-free or you want to conserve backpack space, WAATR sells a carrying handle that you can use to attach the bottle to the outside of your backpack or your clothing.

In all, the CrazyCap gets top marks from us for ease of setup and use, and was one of the simplest, most convenient portable water filters we’ve ever reviewed.

Treatment Time

We also wanted to test how long it took for the water treatment process to be carried out from start to finish.

As we mentioned, the CrazyCap has two modes:

  • Normal mode, which is activated by tapping the button on the lid twice
  • Crazy mode, which is activated by tapping the lid five times
Crazy cap sterilization
Using the Crazy Mode sterilization

We used the 500ml (or 17-ounce) bottle. Normal mode had a 60-second purification time, while crazy mode had a 120-second sterilization time. That meant, if we wanted to use the fastest 60-second normal mode, it took around 2 minutes to purify 1 liter of water – not bad given that we could simply sit back and let our water purify.

There are some limitations when it comes to treatment time and bottle capacity, though. Theoretically, you could use the bottle to sterilize batch after batch of water, then transfer it into separate water bottles or a big water dispenser. But the water treatment time is going to add up, even if you have the slightly larger 740ml bottle. We think the CrazyCap is best used as a personal solution or for small groups, given the bottle size and purification time.

📑 Filter Testing & Certifications

The CrazyCap has been independently tested to kill the following pathogens:

The CrazyCap has also been tested by the NSF to Standard 55, for microbiological reduction – you can view the test report here.

WAATR has a page dedicated to lab reports supporting the CrazyCap’s performance, which is a good place to read up on the purifier’s performance. They’ve also shared an EPA study on the effectiveness of UV water treatment to kill various microorganisms in water.

The manufacturer has given us every reason to trust the CrazyCap’s performance, with comprehensive performance testing to validate their claims. In this category, we couldn’t ask for more.

🔧Setup & Maintenance Considerations

We’ve already mentioned that we found the CrazyCap one of the easiest water purifiers to set up. It doesn’t have a filter, so we didn’t have to prime or soak it before we could use it. We just had to charge the bottle lid, which is also super easy because the charger doesn’t have a USB port – we simply placed the charger on the cap and left it for 4 hours.

The most important maintenance point is that the CrazyCap’s UV light will only work when the device is charged.

We could check the battery life by tapping the bottle lid once. There’s no battery life indicator as such, but the lid glowed green when the UV light had more than 50% charge left; orange when it had 25-49%, and red when it had less than 25%. That meant, as long as we remembered to check the lid occasionally, we always had plenty of warning when the lid would need recharging.

We knew when the cap was charging because it emitted an orange light. Once fully charged, the cap glowed green.

Refreshingly, we didn’t have to clean or wash out our water bottle because the CrazyCap’s UV light keeps the bottle clean. It activates its UV function every hour to self-clean the inside of the bottle, eliminating the need for manual cleaning.

Charging crazycap led uv
Charging the CrazyCap UV LED

🔨 Durability

There’s no avoiding everyday wear and tear, especially if you plan to buy the CrazyCap to use in backpacking or camping-style travel trips. But with its stainless steel design, we were at least confident that the CrazyCap’s UV sterilization ability wouldn’t be affected by the occasional bump and bang.

We used the bottle every day on several hiking trips that spanned 2-5 days on average. The bottle withstood a couple of accidental drops (but we wouldn’t want to do a drop test just in case!). An unexpected challenge for us was locating the charging USB cable – it’s pretty small and we kept forgetting where we’d put it. And speaking of charging, we found that we had to charge the bottle around once every 10-14 days when we were using it consistently.

The cap is designed to provide up to 8 million ounces of drinking water – and considering we drink roughly 64 ounces of water on a daily basis, we could safely assume that with the right treatment, this bottle will would stand the test of time.

The CrazyCap won’t last forever, even if it does have an extremely long predicted lifespan. Eventually, the lid will stop working or the UV bulb will burn out, and there’s always a risk that this will happen sooner than expected. The good news is that it’s easy to buy a new lid online, and the cost is pretty fair given that there are no other maintenance costs to think about.

🤔 Is the CrazyCap UV Purifier Right for You?

In our opinion, the CrazyCap UV water purifier is a really fantastic product and a great fit for anyone who wants the convenience and ease of use of UV sterilizers and is predominantly looking for an effective way to kill bacteria, viruses, and other pathogens from their water. The device is ideal for using as a portable drinking water purification solution, and can be used reliably with untreated, natural water sources.

However, we don’t think the CrazyCap is right for all people or situations. It only kills microorganisms, which means it produces purified water, but can’t physically filter sediment, chemicals, and organics. If you’re looking for a two-in-one water filter and purifier for treating water in the wilderness, the CrazyCap probably isn’t what you need.

Additionally, we don’t necessarily think the CrazyCap is the best investment if you want to filter contaminated tap water, since municipal water supplies are microbiologically safe anyway. Unless you really want the UV purifier because you just don’t want to clean your bottle, we would recommend looking for water filter bottles that can remove the likes of chlorine, heavy metals, disinfection byproducts, and other contaminants that are commonly found in city water.

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  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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