Guest - Not logged in 

Reviews > Water Treatment > Filters > Guyot Designs TapGuard > Test Report by Dawn Larsen

GuyotDesigns TapGuard
Initial Report
Name: Dawn Larsen
Age: 48
Gender: female
Height: 5' 4" (163 cm)
Weight: 165 lb (74 kg)
Email address: vicioushillbilly AT yahoo DOT com
Florence, South Carolina USA
Date:15 April 2009
Backpacking Background
I used to backpack in college a zillion years ago and just in the last two years have backpacked some private trails in Tennessee, Missouri and most recently South Carolina. I have been an avid car-camper for eleven years and I have kayak/canoe camped for four years, both in South Carolina, Tennessee, Missouri and Arkansas. I use a lot of the same equipment for both. I hike hilly/rocky trails especially in Tennessee and Missouri. I moved to South Carolina and am busy checking out the terrain here with my fifteen year-old son.
Product Information
Manufacturer:  GuyotDesigns
Year of Manufacture:  2008
Listed Manufacturer's measurements (on REI website because no listing on GuyotDesigns site): 3 in (76 mm) x 2.5 in (64 mm) x 2.1 in (53 mm)
Actual measurements: 3 in (76 mm) x 2.5 in (64 mm) x 2.1 in (53 mm)
Listed weights (on REI website): 1.6 oz (43 g)
Weight as delivered: 1.6 oz (43 g)
Manufacturer's Suggested Retail Price: $15.95 US
Colors: Tangerine, Tahoe Blue, Black
Product description
The product came packed in a very small recyclable package including the TapGuard, 2 charcoal filters, and instructions.  The packaging says that it removes, chlorine, iodine and other bad tasting chemicals (up to 95%).  It is not a purifier. The packaging also says it is made from "soft food grade silicone" and "fits all wide mouth bottles"
in package contents filter
There is a sticker on each filter packaging that states to rinse under faucet for 1 minute before loading into TapGuard.  The packaging for the cartridges is also very small.

   mfr1  mfr2  images left courtesy of product website
Initial Impressions
Instructions: The instructions are very easy to understand and clear.
Initial Trial:  After rinsing the pouch of charcoal under running water for 1 minute, I placed the pouch inside the compartment at the bottom of the TapGuard.  I put the TapGuard in my Nalgene bottle and it went in easily and tightly.  The first time that I tried to drink out of it, I tilted it too high and spilled water all down my front.  Very funny.  There is a slot where the water from the tap goes in and then you drink from the slot above the filter compartment. When I tilted it too high, it all poured out of the slot where the water should go in. The TapGuard really works!  Our water fountain water at work is so chlorinated that I could never drink it.  It also is a brownish color.  The TapGuard took all the bad taste out of it!  Weeeeeeee!
I (for now) am using it with a Nalgene bottle that has a spout (see picture).  Unfortunately, it won't fit in my small-mouthed stainless steel bottle.  As long as I line up the spout and the filter, it works great.
in bottle
The website is very clear that this product is intended to reduce water bottle usage and not to be used as a purifier.   The fact that the TapGuard is not a purifier may limit it a little, but I think so far, it does what it is intended to do. I look forward to trying it out with my purifier.  My purifier is an ultraviolet light purifier that will kill bacteria, etc., but not take any bad taste out.  I figure this may be a match made in heaven!
Water tastes good
Easy to use
Won't fit in my stainless steel small-mouthed water bottle.

Field Report
20 July 2009 

Field Conditions

I have used the TapGuard daily at work, on hikes, in the gym, and on my bike. I went on a month-long backpacking trip through South Texas, Mexico and Belize 6/18 - 7/18. I used the TapGuard after using an ultraviolet water purifier to purify water on my Texas/Mexico/Belize trip.

Bottles - I have tried this in four different bottles. No stainless steel bottles that I have found will fit it.  The Nalgene pictured above worked for a while and then it began to fall through the mouth of the bottle to the bottom. My Nalgene was old and not BPA-free (bisphenol A plastic, which has been linked to prostate and breast cancer, among other problems).  It did not fit in an Eddie Bauer bottle.  It fell straight through.  I finally found a Camelback bottle that the opening is almost too small for it, but it squeezes in there and does not fall in.  This was frustrating. I couldn't tell just by holding a bottle up to my Nalgene because it depends on how thick the plastic is on the INSIDE, instead of the outside where I would usually measure a threaded lid for a purifier or something.  I also had to break into the packaging of the bottles in order to see if it fit and then if it didn't I was stuck with the bottle because I had opened it.

Durability - The first pouch broke about a week into South Texas (around June 20th) filling my waterbottle (my only water for the day's travels) with the carbon granules. It was undrinkable as the carbon particles float.  Having to buy bottled water that day was very frustrating.  If I had been on a trail, it would have ruined my water supply.

Heat/Cold - Prior to the Mexico trip, I froze the TapGuard and thawed it.  The carbon pouch stayed intact.  I also left it in a hot car for a couple of days and besides the water being hot, it tasted fine and the carbon pouch stayed intact.  

Silicone TapGuard - The bottom of the compartment where the filter goes opens up more than I would like it to.  It has opened up once in the bottle and the filter has fallen in to the water.  It also opens a lot when I take the TapGuard out in order to clean the bottle.

Uses - The water drains through the filter MUCH slower than no filter at all. I wonder if I'm really using it correctly.  When the big slot is closed, the water drains very slowly.  If the big slot is open to allow air, it also allows the water from the bottle to leak around it without filtering it first.  It works. The water tastes good.  

What I Like
It works! Water tastes good.
I appreciate their dedication to the environment

What I Don't Like
Won't fit a stainless steel bottle that I have tried.
The compartment where the filter goes opens up sometimes.
Drains very slowly.
The first pouch broke.

Long Term Report
9 September 2009

Field Information
I have used the Guyot TapGuard in my water bottle daily.  I carried it to work, in the car, at the gym and at home. In my area of South Carolina, the main problem with the city water is chlorine and iron.  Most of the water that I drank was room temperature (approximately 75 degrees F [24 C]), though I did leave the bottle in the car on a couple of hot days and drank the water then. I only froze the bottle once with the filter in and after the filter broke during the Field Report period, I didn’t try to freeze it again.

Test Results
Though the TapGuard worked great to filter bad tastes from water, there were several problems that persisted once I found a bottle that it would fit it well. It drains very slowly. I found that I was often tipping the bottle up too far and the water was leaking through the large opening in the top of the TapGuard instead of through the filter, so I was drinking unfiltered water. As well, it is awkward to use. Several times, water dribbled down my front. That could be user error, but when I was on the treadmill at the gym or hiking, I just wanted a drink fast. I didn’t want to stop and position the bottle and my mouth.

I also found that the bottom tab that seals the cartridge in the TapGuard came open a lot, especially if I bumped or jostled the bottle. Then, I would have to reach down into the bottle and get the cartridge. I didn’t want to do that until I had a chance to wash my hands. It happened enough that it became really inconvenient to use it.

After the first pouch broke during the Field Report section, I'm not really sure that this product is reliable, or a good value for the money, especially if I have to buy two pouches to make sure one works. As well, where I live, we have one outdoor store and they don't carry the pouches. I would have to purchase them online and pay shipping.


I really appreciate their commitment to the environment and wish the product was designed a little better. Because of my commitment to the environment, I plan to keep the bottle that I used it with and the TapGuard at work to filter drinking fountain water. However, I will probably never take it into the field or to a situation where I could not easily replace water if the cartridge broke.

What I liked

It really worked to filter the taste of chlorine and iron.
Guyot's commitment to the environment is impressive.

What I didn't like
It is difficult to use correctly.
The cartridge falls out into the bottle.
The cartridge broke.

This concludes my report. Many thanks to GuyotDesigns and for providing the TapGuard for testing. – Dawn Larsen.

Read more reviews of Guyot Designs gear
Read more gear reviews by Dawn Larsen

Reviews > Water Treatment > Filters > Guyot Designs TapGuard > Test Report by Dawn Larsen

Product tested and reviewed in each Formal Test Report has been provided free of charge by the manufacturer to Upon completion of the Test Series the writer is permitted to keep the product. Owner Reviews are based on product owned by the reviewer personally unless otherwise noted.

All material on this site is the exclusive property of
BackpackGearTest software copyright David Anderson