STORING TAP WATER - Tap Water Shelf Life - While you can use commercially bottled water, you can also store water straight from your kitchen faucet. Once you have filled the container, it should be tightly sealed and stored in a dark, cool location. The water should be rotated out about every six months. It won't necessarily go "bad," but you may get some algae on the container and there is a slight risk of bacterial growth after several months of storage. If the water starts to turn green, use it to water your plants; then clean the container, and refill it with fresh tap water. Similarly, discard the tap water if it develops any other discoloration or has an "off" odor.

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Storing Tap Water

Does Tap Water Go Bad?

Tap Water Shelf Life

by Anne Marie Helmenstine, Ph.D. 

Bottled water has a long shelf life. It lasts essentially forever, as long as the seal hasn't been broken, though it might not taste great a year or more post-bottling.

Can tap water also be stored indefinitely? Homeland Security recommends households keep at least one gallon of water per person per day for three days in case of an emergency.

While you can use commercially bottled water, you can also store water straight from your kitchen faucet.

The Federal Emergency Management Agency (FEMA) recommends storing tap water in clean plastic, glass, enameled metal, or fiberglass containers.

Once you have filled the container, it should be tightly sealed and stored in a dark, cool location.

The water should be rotated out about every six months. It won't necessarily go "bad," ​but you may get some algae on the container and there is a slight risk of bacterial growth after several months of storage.

It is generally suggested to discard bottled water within two weeks after you open it, but FEMA's recommendation for how long you can keep tap water is quite a lot longer.

If the water starts to turn green, use it to water your plants; then clean the container, and refill it with fresh tap water. Similarly, discard the tap water if it develops any other discoloration or has an "off" odor.
Anne Marie Helmenstine, Ph.D.

Introduction

Ph.D. in biomedical sciences from the University of Tennessee at Knoxville - Oak Ridge National Laboratory.

Science educator with experience teaching chemistry, biology, astronomy, and physics at the high school, college, and graduate levels.

ThoughtCo and About Education chemistry expert since 2001.

Widely-published graphic artist, responsible for printable periodic tables and other illustrations used in science.

Experience

Anne Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education since 2001, and other sciences since 2013. She taught chemistry, biology, astronomy, and physics at the high school, college, and graduate levels. She has worked as a research scientist and also abstracting and indexing diverse scientific literature for the Department of Energy.

In addition to her work as a science writer, Dr. Helmenstine currently serves as a scientific consultant, specializing in problems requiring an interdisciplinary approach. Previously, she worked as a research scientist and college professor. 

Education

Dr. Helmenstine holds a Ph.D. in biomedical sciences from the University of Tennessee at Knoxville and a B.A. in physics and mathematics with a minor in chemistry from Hastings College. In her doctoral work, Dr. Helmenstine developed ultra-sensitive chemical detection and medical diagnostic tests.

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https://www.thoughtco.com/does-tap-water-go-bad-3975981