For me, the first sign is repetition combined with minor changes. A single slow drain is normal, but when it repeats with a slight gurgling sound or a brief odor, I stop guessing. Last year, we experienced this problem, and quickly cleaning the pipes stopped helping. I called in professional pipe cleaners to solve the problem, and the improvement was immediate. I contacted
https://bens.plumbing/areas/capitol-hill/drain-cleaning/, which finally figured out what was deep inside the pipe. After that, the drain remained stable and the noises disappeared. Now these early signs tell me that I need to address the cause at an early stage, rather than repeating short-term measures that only buy time. It has also changed how I monitor the performance of multiple plumbing fixtures simultaneously during busy morning hours and rainy weeks.