Martin,

To me a manometer is a device used to measure the pressure (of gases) or pressure differential (e.g. indoor vs. and outdoor). Is this what you are considering using? I don't see a great need for this device in a typical home inspection.

If you are doing energy audits and using a blower door then the pressure differential (indoor vs. outdoor) would be very important. Also, if you are doing radon testing and find elevated levels of radon the pressure differential would be important because a house with a significant negative pressure may be drawing in radon in through the foundation.

If you are talking about a water level to measure levelness of floors a good one is the Zip Level Pro-2000. It costs around $800 (last time I checked). It is on my wish list but I don't have a pressing need for it.

You can measure how much out of level a floor (or beam, etc.) is BUT unless you know it was originally perfectly level you cannot say exactly how much it has moved.

For example, let's say you check the four corners of a rectangular house. The right-rear corner is 2" lower than the left-front corner. Can you say the RR corner has dropped 2"? (I can't & I wouldn't.) All you can tell your client is that the RR corner is presently 2" lower than the LF corner. If you can monitor the house over time you should be able to tell if the house is actively moving. A year down the road if you measure a differential of 3" you could report with reasonable certainty that the house is moving (either the RR corner is dropping or the LF corner is rising or both).

You might want to check with your state's Board of Registration for Engineers and find out if measuring or monitoring the levelness of floors, etc. is considered practicing engineering. If so, unless you are a registered engineer, you should find something else to add to your tool bag.

__________________
"Baseball is like church. Many attend but few understand." Leo Durocher
Bruce Breedlove
www.avaloninspection.com