Lots of good advice on this forum for this fairly common Alpine issue. What kind of solution you choose, depends on where the leak is. A failed joint is easier to fix. A broken ABS elbow or pipe is a lot tougher. Access to the area is always a challenge. Recently, I downsized and used a 1 inch pool hose and doubled up with cementing PVC couplings, covered with rubber boots with hose clamps. Even new, 1 1/2" pool hose is very stiff, so I used 1 inch--not so stiff. Also, ribbed hose is really hard to seal on the outside and can/might trap debris on the inside.
2003 Alpine 40' MDTS
New Braunfels, Texas