I am a plumber and I recently completed a job at a client's home. The client had us out to flush their water heater. The water heater was 5 years old and had a lot of sediment in it. We were able to flush it out and it worked fine. However, the client did not want us to replace the water heater because it was so old. We also noticed that the water heater did not have an expansion tank, which is important for preventing thermal expansion. The TMP (temperature and pressure relief valve) was dripping, indicating that the tank was working harder than it should be. The rest of the home appeared to be in great condition, with PVC for the drain line and copper water lines. Overall, the job went well, and the client was happy with the results.