Water-to-Go Active Filter Bottle review

What it is

Water-to-Go sells the Active as a 75cl filtered water bottle: you fill it from a tap, stream or water butt, screw on the lid and drink through the filter. Replacement cartridges come as a twin pack the maker titles 200-litre filters, so each cartridge is rated for about 200 litres before it needs changing.

That figure is the important number to keep in mind. At two litres a day, one cartridge covers roughly three months of daily use, which makes the Active a bottle you live with and replace parts on, rather than something you seal in a kit and forget.

What the lab test showed

The evidence Water-to-Go publishes is a report from the London School of Hygiene and Tropical Medicine dated 8 May 2013. Two bottles were challenged with poliovirus type 1, E. coli bacteria and fluorescent beads sized to stand in for Cryptosporidium oocysts. Poliovirus fell by 99.982% in one bottle and 99.937% in the other; E. coli by 99.9992% and 99.9837%; the beads by at least 99.98% in both. Free chlorine dropped from 60 ppm to under 0.4 ppm.

Read that carefully. The test used laboratory water rather than muddy river water, it is more than a decade old, and the Cryptosporidium result comes from a bead stand-in rather than live parasites. We found no claim of certification to an NSF or US EPA purifier standard. It is still more virus data than most squeeze bottles publish.

Where it fits in a UK home

In Britain the realistic emergency is a burst main, a supply interruption or a boil water notice, not a trek across a desert. In those events the first rule is to follow your water company's instructions, and our boil water notice guide and emergency water purification guide set out what that means. A filter bottle is a convenient extra for a grab bag or a car, and it improves the taste of chlorinated tap water day to day.

It is not a substitute for stored water. Our guide to storing emergency water covers how much to keep for each person in the house.

How it compares

On the comparison the LifeStraw Peak straw and Sawyer Mini filter far more water for their size, rated at 4,000 litres and well beyond respectively, but they make no virus claim. The GRAYL GeoPress is the stronger purifier, claiming 99.99% of viruses to a US EPA guide standard, at 450 g empty and with a 250-litre cartridge. The Active sits between them: lighter and simpler than the GRAYL, with some virus evidence the straws lack, but the shortest cartridge life of the group.

Our verdict

Buy it if you want one bottle that earns its place every day and can also handle questionable water on a trip or in an outage. Skip it if the bottle is only for a kit you hope never to open: a straw rated for thousands of litres is the better long-term store, and stored water comes first either way. Write the cartridge start date on the bottle so you know when it reaches 200 litres.

Does the Water-to-Go Active remove viruses?

Water-to-Go's published 2013 test from the London School of Hygiene and Tropical Medicine recorded poliovirus reductions of 99.982% and 99.937% in two bottles. We found no certification to an NSF or US EPA purifier standard, so treat it as good evidence rather than a formal rating.

How long does a Water-to-Go filter last?

The maker sells replacements as 200-litre filters, so plan on changing the cartridge after about 200 litres, which is roughly three months at two litres a day.

Can I use it instead of boiling water during a boil water notice?

Follow your water company's notice, which normally says to boil water for drinking until it is lifted. A filter bottle is an extra, not a replacement for the instructions you are given.

Is it worth it over a filter straw?

Only if you will use it every day. A straw like the LifeStraw Peak is rated for 4,000 litres, which suits a sealed emergency kit much better than a 200-litre cartridge.