There's a book about a heroine that had to have enemas every day, but she had Hirshsprungs disease, a segement of the bowel was paralized and nothing would pass easily past this for her since birth, so it was enemas or a build up of material in the colon until it rotted then diarrhea. That was 1900, now a simple surgery removes the bad segment soon after birth and the probem never occurs.
But to the habit of doing them every day. Dr. John Kellogg, who was still doing sugery at age 91, took a daily colonic irrigation which is much more washing than an enema. I have had one patient in her mid ninties who took daily enemas for over 70 years that was in good health. So, it may not be harmful. I think it is too much heat, what you put in the water, if the water is chorinated, etc that can create a problem.
In general I don't recommend daily enemas, nor enemas at all unless there is a clinical reason. For me, I am older, have diverticulosis, if I had someone to give me daily good enema I would do it because washing these out would help them shrink, plus keep this problem spreading to other haustra. If I had had more healthful good enemas routinely through my life, I probably wouldn't have diverticulosis, but I have not lived perfectly and do.
If you are going to take them frequently, which I don't recommend, then try to have a normal BM each day as well. You can do this by timing. Take some prune juice with a few teaspoons of psyllium husk in the evening, enough to stimulate a good morning BM. Then if you take a good enema fairly soon after that, the system has worked both ways, you just need enough bulk stimulation to have a natural BM followed by the enema. With this you may also find that if you have to travel and not have enemas, that during the day you may be a little more slugish, but your bowel funcion remains OK.
Daily enemas you need to be sure not to over relax the colon, use water just above body temperature, 100 degrees fahrenheit, and be sure it is balanced using preferably baking soda to alkalze and make neutral to the body, about a level tablespoon per qt. Plain water is an irritant to the colon. And be sure the water is clean you are much more vulnerable via rectum to bacteria than if you drink it, not city water, or city water that has been boiled and let sit to cool to room temp to get the chlorine out. The healthful bowel has a lot of good bacteria in it. A single enema won't likely wash it out, but chlorine in the water will kill it.