# City water bad for my plants? **URL:** \ **Category:** Factual Questions\ **Created:** [June 5, 2015, 1:46am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674 "2015-06-05T01:46:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 1:46am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/1 "2015-06-05T01:46:21Z")
I’ve noticed that watering my gardens (vegetable & flower) with city water during extended periods of lack of rain seems to just keep my plants alive, they don’t thrive. When it finally rains, boom!.. Everything takes off and grows like crazy. After 40+ years of gardening, I know how to properly water plants, so it’s not a matter of technique. Any ideas? ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [June 5, 2015, 1:53am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/2 "2015-06-05T01:53:26Z")
Rain waters the plant, as well as the soil. Humidity levels are typically higher during rain storms, which may also be beneficial. Apart from that there is no difference in rain water and municipal water, as far as the plants are concerned. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 1:57am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/3 "2015-06-05T01:57:29Z")
> [@Leaffan](#): > > Rain waters the plant, as well as the soil. Humidity levels are typically higher during rain storms, which may also be beneficial. Apart from that there is no difference in rain water and municipal water, as far as the plants are concerned. I beg to differ, but there has to be a difference. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 5, 2015, 2:03am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/4 "2015-06-05T02:03:49Z")
> [@ZurBob](#): > > I beg to differ, but there has to be a difference. Why did you ask the question, if you don’t want the answer? If your city water is fit to drink, it’s fine for plants. Just look at the endless houses, buildings, and golf courses that are watered with municipal water. ---
**Author:** ![Mangosteen](https://avatars.discourse-cdn.com/v4/letter/m/6a8cbe/32.png) [@Mangosteen](https://boards.straightdope.com/u/Mangosteen)\ **Post date:** [June 5, 2015, 2:13am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/5 "2015-06-05T02:13:48Z")
Rain water has traces of nitrogen, which plants like. City water doesn’t. In the southwest, city water can contain high amounts of sodium, which plants don’t like. Get some large barrels and save that rain water. (Just be careful. In some jurisdictions, its illegal to catch rainwater.) ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [June 5, 2015, 2:15am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/6 "2015-06-05T02:15:01Z")
Well, there are chemicals in city water, if you want to test it you could go to the pet store and pick up some Prime to get rid of the chlorine and chloramine and see what happens. Also, I know you said you ‘know how to water’, but are you watering long enough to saturate the soil down a good 6 or 12 inches? I always find it funny when I see people put a sprinkler on their lawn and then move it every 10 minutes. In reality, you need to leave a sprinkler in each spot for about 2 hours to get the water down 6 inches or you’ll end up with shallow roots and bad grass. In fact, it’s even worth it to water your grass _while_ it’s raining. Get a half inch of rain and use that time to put down another 1-1.5 inches of water. Similarly, I see people just turn on the hose, run it along their flower bed and call it a day. The water probably doesn’t make it down more than a half inch, much less to the roots. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 2:31am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/7 "2015-06-05T02:31:18Z")
> [@beowulff](#): > > Why did you ask the question, if you don’t want the answer? Never said I didn’t want “the” answer. But, apparently as you perceive it, the first reply was conclusive… END OF DISCUSSION. However, don’t you think it’s a little presumptuous on your behalf, to declare my question moot at this time? ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 2:40am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/8 "2015-06-05T02:40:06Z")
> [@Mangosteen](#): > > Get some large barrels and save that rain water. (Just be careful. In some jurisdictions, its illegal to catch rainwater.) Have for years. 55 gallon barrels x 6… with a pump. When it runs out is when the trouble begins, watering with city. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 3:02am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/9 "2015-06-05T03:02:40Z")
> [@Joey\_P](#): > > Also, I know you said you ‘know how to water’, but are you watering long enough to saturate the soil down a good 6 or 12 inches? Yes, I am. I’m very conscientious in this matter. I’m thinking chloramine may have some effect in this matter. My instantaneous tap Ph is appx. 11, versus 7.5 after 24 hrs. of rest in an open container. Despite what “beowulff” may blather… There is something fundamentally different between water from the sky and water from my city water tap. I hope those of you here who actually have knowledge of water chemistry, as opposed to the aforementioned blowhard, may be of help. ---
**Author:** ![zombywoof](https://avatars.discourse-cdn.com/v4/letter/z/9e8a1a/32.png) [@zombywoof](https://boards.straightdope.com/u/zombywoof)\ **Post date:** [June 5, 2015, 3:07am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/10 "2015-06-05T03:07:53Z")
I’ve always assumed my plants have done better after rains simply because they’re getting deeper/longer watering than usual (in much the same way as the grass around my air conditioner drain grows like crazy compared to that in the rest of the yard)…but soil chemistry testing is a thing, right? - you might have it done to compare rainwater-saturated vs. city water-saturated soil. ---
**Author:** ![Kiwi\_Fruit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kiwi_fruit/32/12_2.png) [@Kiwi\_Fruit](https://boards.straightdope.com/u/Kiwi_Fruit)\ **Post date:** [June 5, 2015, 3:24am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/11 "2015-06-05T03:24:21Z")
Your city water sounds fairly alkaline to me. Plants have a hard time taking up nutrients if the soil pH is not in the range they require. Some plants like acidic but none too far from neutral (pH = 7) [Acid or Alkaline? What pH means in gardenspeak](http://www.plantea.com/pH.htm) > [@](#): > > Nutrient uptake and pH > > Have you ever been disappointed with the performance of your vegetables or flowers, even though you gave them the best care you could? Truth is, pH might have been the problem. Plant roots absorb minerals such as nitrogen and iron only when they are dissolved in water. Now if this soil “soup” solution (the mixture of water and nutrients in the soil) is too acid or alkaline, some nutrients won’t be dissolved, and as a result, they are unavailable to plants. They are said to be “locked up.” > > To put it another way, if the pH isn’t close to what these plants require, some nutrients, such as phosphorus, calcium and magnesium, can’t be dissolved in water. And since plants drink their food instead of eating it, if the nutrients aren’t dissolved first, the plant can’t absorb them. Thus, your corn, lettuce, roses and geraniums won’t grow or produce to their full potential. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 3:28am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/12 "2015-06-05T03:28:07Z")
> [@zombywoof](#): > > soil chemistry testing is a thing, right? - you might have it done to compare rainwater-saturated vs. city water-saturated soil. Done. The only discernable difference is the Ph: 7.6 for city, 7.1 for non city dependent areas. Not enough variance to explain the vast difference in growth patterns. Thanks. ---
**Author:** ![newme](https://avatars.discourse-cdn.com/v4/letter/n/e0b2c6/32.png) [@newme](https://boards.straightdope.com/u/newme)\ **Post date:** [June 5, 2015, 3:31am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/13 "2015-06-05T03:31:09Z")
> [@Leaffan](#): > > Rain waters the plant, as well as the soil. Humidity levels are typically higher during rain storms, which may also be beneficial. Apart from that there is no difference in rain water and municipal water, as far as the plants are concerned. Try growing a vegetable garden which gets heavily mineralized city water but no rainwater for the entire month of July, then come back and tell me if it makes no difference. After a rain free month, you will see a white crust start to form on the soil from the accumulation of salts. I always say the plants look like they are smiling when they get that first drought-breaking rain, which washes the salt away. ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [June 5, 2015, 3:33am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/14 "2015-06-05T03:33:06Z")
LA gardener here. My water is very hard. I quickly get visible deposits on new drip irrigation outlets; sometimes they get so crusty I need to replace them. I’m a dilettante so I haven’t investigated which plants don’t like this, but I have noticed some mysterious deaths that don’t seem related to bugs or lack of water. ETA, I’ve never seen a white crust develop on the soil, as **newme** describes. I do make an effort to renew the soil in my pots, and when I was planting in beds more I did there as well. ---
**Author:** ![ZurBob](https://avatars.discourse-cdn.com/v4/letter/z/71e660/32.png) [@ZurBob](https://boards.straightdope.com/u/ZurBob)\ **Post date:** [June 5, 2015, 3:46am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/15 "2015-06-05T03:46:00Z")
> [@newme](#): > > Try growing a vegetable garden which gets heavily mineralized city water but no rainwater for the entire month of July, then come back and tell me if it makes no difference. . Not sure what you are asking here BUT… Last July I watered almost exclusively with city… Plants didn’t grow much, yellow crust formed on soil. Upon first soaking rain in early August, plants took off with a growth/flowering spurt. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [June 5, 2015, 6:58am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/16 "2015-06-05T06:58:22Z")
**Moderator Note** > [@ZurBob](#): > > I hope those of you here who actually have knowledge of water chemistry, as opposed to the aforementioned blowhard, may be of help. Calling someone a blowhard is a personal insult, and personal insults are not allowed here outside of the BBQ Pit. Don’t do this again. A good rule to follow is attack the post, not the poster. ---
**Author:** ![Leaffan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leaffan/32/299_2.png) [@Leaffan](https://boards.straightdope.com/u/Leaffan)\ **Post date:** [June 5, 2015, 8:16am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/17 "2015-06-05T08:16:52Z")
> [@newme](#): > > Try growing a vegetable garden which gets heavily mineralized city water but no rainwater for the entire month of July, then come back and tell me if it makes no difference. After a rain free month, you will see a white crust start to form on the soil from the accumulation of salts. I always say the plants look like they are smiling when they get that first drought-breaking rain, which washes the salt away. I don’t believe this in any way. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [June 5, 2015, 10:37am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/18 "2015-06-05T10:37:57Z")
Our water is hard and alkaline, and I’ve also seen the white crusty buildup mentioned, especially in potted plants. At that point, the soil seems spent, too: it doesn’t have the richness (smell & touch) of compost, for example, ands plants in it don’t thrive. So this longtime gardener and fish keeper says there IS a difference between the cleanest of rainwater (hi, urban “acid rain!”) and some of the worst of available municipal water, and of course there’s a gradient or bell curve for the quality of each so some rain water is way WORSE than some cities’ water. I’d also suggest that some of the immediate effects on the plants are due to cooler air temps during and immediately after rain, just from the clouds blocking the sun. ---
**Author:** ![JoshuaSD](https://avatars.discourse-cdn.com/v4/letter/j/f1d935/32.png) [@JoshuaSD](https://boards.straightdope.com/u/JoshuaSD)\ **Post date:** [June 5, 2015, 11:07am UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/19 "2015-06-05T11:07:34Z")
Hydroponic person here. Hydroponics poses a new wrinkle to this very issue for me. Impurities will slowly clog up my filters and hoses limiting water flow and even oxygenation of the water. Spring to fall I am using collected rainwater only but as winter approaches and the rainwater freezes I switch to tap water. Net effect on filters, hoses and aerators, white crusty (calcium?) deposits. Net effect on plant and fruit harvest, none. I had the exact same tomato yields, kumquats were rocking all winter long, lettuce was just as tender and insanely abundant and I saw no increase or decrease in herbs. Net effect on water bill was not negligible but also not really that big a deal in my area. I go back to the rain barrel in the spring from a cost and “eco” standpoint not for the health of my plants which do just fine either way. For the record, because I think location matters a lot in this, I’m in Montgomery County Maryland. Urban/Suburban neighborhood with no unusual water issues I know of. ---
**Author:** ![Hermitian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hermitian/32/470_2.png) [@Hermitian](https://boards.straightdope.com/u/Hermitian)\ **Post date:** [June 5, 2015, 1:49pm UTC](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674/20 "2015-06-05T13:49:02Z")
> [@Leaffan](#): > > I don’t believe this in any way. So, you deny the existence of [hard water](http://en.wikipedia.org/wiki/Hard_water), which leaves mineral deposits on things? You have to at least acknowledge that municipal water is not indistinguishable from rainwater. To some degree, they are different. How those differences affect or do not affect plants, well that’s a question that people are trying to figure out. [Next page](https://boards.straightdope.com/t/city-water-bad-for-my-plants/721674.md?page=2)