Unidentified plumbing items

I am just starting out in home inspection. I have a couple of plumbing items I am not familiar with. The first one is a tank on top of a H2O heater. It is T’d off the cold water supply.

The second is under the kitchen sink. I know the appliance on the left is an RO system, but what is the white tank? The label says “For salt or service call…” so I assume it is a softener or conditioner, but not like any water softener I have ever seen.

Sorry about the sideways pictures, but I don’t see a way to adjust that on this forum.

Thanks for helping out the newbie!

The 1st one is a expansion tank. An expansion tank prevents pressure increases due to thermal expansion of your water. As your water is heated from 50° F to 120° F, it expands by approximately 2%.

If you have a “closed system”, which means there is a backflow preventer or other device that prevents your water from flowing back into the water main, thermal expansion will cause very rapid pressure increases in your plumbing system.

And the 2nd one is storage tank that holds the RO (reverse osmosis) processed, high-quality water until needed.

Using google is a good way to assist you.

I did know reverse osmosis required salt.

I did know reverse osmosis required salt.

The house may have a softener too. Installer must have put sticker on there.

Generic label… thus the “or”.



I strongly suggest that you get more HI education. REA’s will hire you because you lack HI knowledge, and have a better chance of not alarming the home buyer. This can lead to an attorney call. Read and study every InterNACHI inspection articles and CEU tests.

Education deficient.

May I suggest at least wondering the big box store near you until you understand what everything they have is for?

Your pics show very basic stuff. Education is key.

Thanks to everyone. All very good advice. As I said, I am just starting out. I do realize I have a lot to learn, and do plan on taking every InterNACHI course I can. Forums like this are also an excellent source of education. What is “basic” to an experienced expert is new knowledge to someone just beginning. I have a lot of “basic” knowledge about Air Traffic Control which I bet most of you don’t have a clue about, but I would welcome an opportunity to share it with you rather than tell you it is basic knowledge and you need to go find your own answers.

Excellent! Thank you!

Thank you very much for the clear and to the point answer.

Your choice of a new career comes with the responsibility to be educated well enough to do your job and gain the respect of your clients and others involved in hiring you for your professional opinions.

Taking offense at innocent comments is what exactly?

Perhaps this was a practice inspection in which case my comments would have been entirely different.

I was just pointing out that having stated I was just starting out should imply I have a lot to learn. That is why I turned to you experienced professionals here on this forum for answers. Whether it was a practice inspection or not is irrelevant. It is the responsibility of experts in their field to act as teachers and willingly pass their knowledge along to those wanting to learn.

To my question, one reply-or provided an explanation, two sent very helpful hyperlinks, and the discussion even provided a logical explanation for the “for salt” sticker on the RO tank. The advice to utilize InterNACHI’s educational resources is sound.

Your “innocent comments” were in no way helpful or even attempted to answer my questions. “Innocent comments” such as “education deficient”, go wander around a store until you understand everything, and your questions are basic stuff, were condescending and completely blew off my questions and concerns. Your comments did not allow me to access your knowledge in order to learn from you and your experience.

Your expertise and knowledge were gained through years of experience. I am working on gaining as much knowledge as I can as quickly as I can. When someone asks a question, be a teacher, not a judge.

Allan, you getting on here and start to lecture people is going to create a very big problem for you. You will step in the bucket quickly. Toughen up your skin or don’t ask. Experienced people here will be happy to help, unless the question is so basic as to demonstrate a very early entry experience. Ask if you can’t find it, but at least look on your own first.
Take the advice given. Go to a big box store and look around. Take the classes. Talk to trades people. But don’t lecture the members here.
Kind of like me showing up as a beginner at an ATC site and asking how those big muther planes fly.

You’re right, Greg. Thanks.

Allan, are you still a student inspector?
The message board is a great place to have questions asked and answered, some will criticize, however it is all with good intensions, the message board thrives because of inspectors asking and getting answers. it can be a tough place some times.

Yup, still a budding student. I fell into the social media hazard that the printed word carries no inherent intent or tone and you should never assume you know the writer’s motivation or tone. Even emoji’s don’t always do the trick. (and I knew this dammit!) Thanks for the note.