Landlord wants to charge me for plumbing costs

My Landlord wants to charge me for dehumidifier equipment rental which will be like $900 for an under the kitchen sink leak. He said I should have informed him immediately. I know I should but when I saw it leaking I noticed the tubes were lose so I tightened them, and it stopped leaking. A few days later I saw him and informed him of the leaking tubes he then took a look and noticed the tubes were still leaking and there was water on the bottom kitchen counter. He said the bottom counters had gotten wet and he would have to dry them out he never mentioned any costs or that I would have to pay. I assumed he would take care of it because that is what he works on. The next day he came with a dehumidifier and 3 smaller fans he supposedly rented from his job. He left them for 3 days straight without checking up on them, which he said he would come everyday to look at them. On the 4th days he came and took 2 smaller fans with him and said tomorrow he would come for the rest because it was still a little damp and he told me he would charge me for the rental. I don’t think I should have to pay because it wasn’t my fault he didn’t change the tubing the first time this happened a few months prior to this incident. He should have also informed me he was going to charge me for any damages. That way I could have gotten a second opinion I don’t know if he made this a big deal to get money out of this he doesn’t even have proof of any damages caused its only his word. I took pictures before and there doesn’t show any wet spots or damages. How do I know he didn’t leave the dehumidifiers longer just to charge me more?