Precision hydrostatic level and flatness measuring device, system and method

A water-holding cup for use in connection with a hydrostatic system for measuring with precision, a level normal to gravitation of a surface, said cup comprising:

• a cup height h thereof from a bottom to a top of said cup when said cup is resting upon the surface, which cup height h is known a priori within acceptable measurement errors;
• mirroring on a bottom surface of said cup;
• and
• at least two water outlets for fluidically interconnecting said cup with other like-cups, said outlets oriented at a fitting angle of at least five (5) degrees downward;
• wherein:
• when a micrometer is physically aligned to said top of said cup and a probe tip at a lower extremity of said micrometer is extended to contact the top surface of water within said cup thereby forming a meniscus when said contact occurs, the user is able to see when the meniscus is formed by the reflection of light from the meniscus against said mirroring, and is enabled from the micrometer extension when the meniscus is formed, to ascertain a distance d between said top of said cup and said top surface of said water within said cup;
• and
• the user is further able to deduce with precision, a level 1 of the water surface within said cup above said surface by the relation l=h−d.