Yes, submersible water pump (you can get them specifically for birth pools) but I imagine you could get a much cheaper one at like B&Q. Also, as far as clean up, tell your husband not to stress about it. I had a home birth and though I didn't give birth in the pool (I actually didn't like it as much as I thought), it still needed to be emptied. I have no idea who did it or how, but before the midwives left it was done. One of them just did it and cleaned up for us.
Also, lots and lots of towels and shower curtains for keeping you and your floor dry. Get twice as many as you think you need because you might end up moving around more than you think. I ended up wandering around my upstairs between the bathroom and bedroom in between pushing (who knew that would be possible or comfortable?!?) and when the time came for my daughter to be born, most of the floor coverings were in the lounge under and around the pool. I gave birth in my bedroom squatting on the floor and the poor carpet did take a bit of a hit.
Also, think about whatever you need in order to get the atmosphere to be just right for you. I had aromatherapy oils burning, candles and fairy lights lit, my relaxation music playing, etc. And plan the snacks and drinks both you and your partner might need. I had tea and porridge with honey in early labour, and then was eating honey, dates and glucose gel once I was pushing. I also drank nearly 3 litres of coconut water. That stuff is great! I had lots of biscuits and granola bars for the midwives and my husband (and whatever else was in the kitchen they wanted).
It's great you're planning a home birth. Though I wasn't as keen as I'd hoped on the water (I hate baths and swimming, so it's no surprise, and I was fine managing the pain without the pool), having my daughter at home was the best thing I could have ever done. I sometimes doubt plenty of other parenting choices we make, but home birth is the one thing I've never doubted. It was wonderful and I'm so proud of myself (and my husband) for giving her that start to life.
Love being able to read positive things about homebirth 
. In the end I decided no to a homebirth because I really had a bad feeling they would be looking for things to go wrong and then bully me into transferring to hospital for no sound medical reason- even though they admitted they had attended births of women who were into double figures and they had no complications to deal with, I am only on baby number 5. Unfortunately they know all too well that at that stage of pregnancy women aren't exactly in fight mode and are very likely to just back down if there is any opposition 
My poor mum and DH had to empty it with buckets! Still, it only took half an hour or so. The midwives also helped out with cleaning everything up and it didn't take long at all.
