indoor coffee plant
Plant is growing well, but lower leaves have become marked with brown discolouration.Water with rain or tap water, please?
Although tap water will be fine, rainwater is always a better choice. Can you include a photo? It could be that it needs to be fertilized depending on how long it has been in the same soil. If it has remained too wet for too long, it could also be a bacterial or fungal infection. A photo would help me better diagnose the issue.