1. Blocked sunroof drains: If the sunroof drains are blocked, water can accumulate and overflow into the passenger compartment. To check the sunroof drains, open the sunroof and pour water into the channels on either side. If the water doesn't drain out freely, the drains are likely blocked.
2. Faulty door seal: A faulty door seal can allow water to seep into the passenger compartment when it rains. Check the door seal around the passenger door for any cracks or damage. If the seal is damaged, it will need to be replaced.
3. Faulty windscreen seal: A faulty windscreen seal can also allow water to leak into the passenger compartment. Check the windscreen seal for any cracks or damage. If the seal is damaged, it will need to be replaced.
4. Heater matrix: If the heater matrix is leaking, it can cause water to leak onto the passenger-side footwell. Check the heater matrix for any signs of leakage. If the heater matrix is leaking, it will need to be replaced.
To fix the water leak, you will need to identify the source of the leak and then take the appropriate steps to repair it. If you are not confident in your ability to carry out these repairs, you should consult with a qualified mechanic.
