My Tankless Experiment

Probably not long

Slightly off topic, perhaps, but Mark -- did you investigate the old WH to see why it started leaking? I'm considering a powered anode to eliminate any electrolytic issues, but if these things just up and decide to start leaking for more basic reasons, it's probably a waste of money. But fabricating a tank to hold water at 100psi for 25 years or more doesn't seem like rocket science.