Water quality can have surprisingly high impact on QoL (just as air purifiers can significantly improve QoL), and some steps (like getting the right pitcher have very high return on time/attention invested). There still isn't a LW thread on water quality so I'll post it here. 

Water may contain disinfection byproducts (eg ), PFAS, microplastics from PVC-based plumbing, and heavy metals. 

There are a variety of water filters - including both pitchers and reverse osmosis. Many of them are made of plastics, but the plastics (eg Tritan) presumably are less "leachable" than more "flexible" plastics. Note that reverse osmosis filters are made of plastics and may leach micronanoplastics. At some point, it would be wise to test all the filters for nanoplastics (nanoplastics being more penetrating and harmful, though still much harder to quantify)

EWG has a site for helping you look up your city's water quality: https://www.ewg.org/tapwater/system.php?pws=MA3049000

Supposedly, Toronto has "better water quality" than most US cities like Boston (@yasmeenbrain on twitter says this).

https://www.cnet.com/home/kitchen-and-household/best-water-filter-pitcher/ is a source of reviews, but there are many review sites (as well as YouTube video reviews).

Some more resources: https://www.crsociety.org/topic/18497-drinkingtap-water-thread-and-ideal-water-filterspitchers/#comment-47188

https://mccormickmd.substack.com/p/surprising-levels-of-microplastics

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I'm always interested in easy QoL improvements- but I have questions.

Water quality can have surprisingly high impact on QoL

What's the evidence for this particularly?

What are the important parts of water quality and how do we know this?

This suggests a (self-)experiment: Drink only filtered water/distilled water with selectively added minerals vs. tap water. Problem is if the effects are really small or really long-term, so we'd need samples that are several weeks long.

Is tap water expected to contain fewer microplastics than bottled water? In this case there's surely some natural experiment[1] that could shed light on whether microplastics are harmful.


  1. Although things like natural disasters which limit tap water access, surges in bottled water prices or tap water contaminations don't count. Maybe the plastic supply chain experienced a disruption due to some natural disaster at some point, similar to GPU prices soaring when there was a flood in Thailand? There was a (small) sudden decline in price for HDPE/LDPE/LLDPE in early 2018, maybe that works. Although it seems like PET didn't have a similar price drop. ↩︎