Filtering on Shabbos With an Inline Filter
Q. I live in New York City and will not drink the city water without filtering it due to the presence of copepods (tiny sea creatures) in the water. In the previous Halacha Yomis we noted that one may not pour water through a filter because it may constitute borer. My faucet has an under-the-sink inline filter that removes the copepods. Am I permitted to run the tap water on Shabbos and use the water? Is this the same as pouring water through a filter which is prohibited?
A. Using the faucet on Shabbos to wash hands or dishes is certainly not an issue because it is unnecessary to filter copepods for these uses. Even washing fruits and vegetables is not a concern because copepods do not stick to food. What about drinking water from the faucet? Rav Schachter ruled that this is permissible for a combination of reasons.
- The Nishmas Adam (16:5) was uncertain if there is any issue with filtering out tiny bugs that you would not find objectionable if not for Halachic concerns.
- The prevalence of copepods in the water is only a safek. Most cups of water will be clean and not need filtering.
- There are Poskim who allow drinking water with copepods.
The Minchas Yitzchok (7:23) writes that there is more room for leniency with regard to built-in under the sink filters. This is because the filter does not remove the bugs from the water. Rather, clean water passes through the filter, and the copepods bugs remain behind in the water in the pipe. Since the bugs are not separated from the water, this is not the melacha of Meshamer (filtering). He offers other arguments as well why this should be permitted.
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The Gerald & Karin Feldhamer OU Kosher Halacha Yomis is dedicated to the memory of Rav Yisroel Belsky, zt"l, who served as halachic consultant for OU Kosher for more than 28 years; many of the responses in Halacha Yomis are based on the rulings of Rabbi Belsky. Subscribe to the Halacha Yomis daily email here.