Ever since moving to a new house, I have had a hard time keeping house plants alive. Even my pothos have struggled, and I have never had problems with those.

I had to repeatedly take dying pothos out of a pot, root the cuttings, then plant again. Finally I decided to get some pots that don't drain, fill them with water and leave the pothos like that. They've been doing fine for a couple months now.

I also had a tall dumb cane that was struggling, as they tend to do when they get too tall. Well, I just uprooted it, cleaned off the roots and put it in a giant vase. It's been like that for about a month and it's lost a couple leaves, but the rest of it looks healthier than before.

Is there any reason why I couldn't just leave this in water forever? I change out the water when I water the other plants.

I also wanted to have more peace lilies around and I know they are pretty thirsty plants, so I wondered if I could just put those in water.

I also have a few 'lucky bamboo' which have been in water for years and, of course, those are fine.

Just about all plants roots have to breath. They need air. Plants die when you overwater them for that reason. Yes, there are aquatic plants that do live in water, but 99.9% of hat you know as house plants will not. Gene

There are some plants that can live in definitely in water. There are many reports of Pothos & Philo vines living for decades in various vessels of water, and countless other less long-lived endeavors. I think my longest was about 8-10 yrs. The end usually comes when there's a lapse in remembering to add water, the plant gets so heavy that it pulls itself out of the water, or gets ill from accumulated toxicity from some chemical in tap water.

My current longest-lived water plants are a jar of vine cuttings snipped a year ago with the intention to start a new pot, then deciding I liked the way the jar & the cuttings looked where they were, and they've just been there ever since. I've never changed the water, just add to it. It's clear and clean looking and the plants look normal, though they grow very slowly. Shoot, I got a phone call while typing & need to go. More next time, & maybe a pic.

In fact, most herbaceous plants can grow in water. It is called hydroponics. In places like Israel, many food crops are grown hydroponically. Closer to home, one of the more popular plants is the Lucky Bamboo that is really a type of Dracaena cutting that is put in a small container filled with water. These water-grown plants develop roots that are able to survive in water. Their long-term limitation is usually lack of nutrients. However, there are hydroponic solutions to remedy that.

There is a reason. If it's not hydroponics as WillC mentioned, the roots of your plant will rot by time, if it's not a hydrophilic plant. Even if you change the water daily, so to ensure better guard against bacteria, they will not last forever. I have read about better results in keeping plants in clay pebbles though, these ones keep the roots hydrated but not soaked and the air supply to the roots is way better as I think of it. I want to try this with some cuttings. The other thing to consider is the flunctuation of temperature of the water. Water cannot be kept in standard temperature without some professional equipment, e.g. aquarium water, etc, it would be cooler at night and gets warmer when the room is heated or gets more sun, depending on many specifics variants (how close is it to sunlight, where is your water jar/pot, etc standing, is it near a heater, is it near an A/C, and so on).
I put a chunk of charcoal in the water when I take cuttings, it helps by keeping it cleaner for longer periods.