Water on the earth

Cosmic abundance of elements (kinds of atoms)
H, He, O, C, ...
Matter making up the earth, and water within it
Mantle, crust ... mainly oxides (SiO2 etc.)
Most of H (written H2O) are chemically bounded in minerals
Core ... mainly iron (Fe)
H also seems to exist, but the quantity is not well known.
In the following discussion, "water" refers to H2O molecules near the surface of the earth.
How much water (in 3 phases) exists, and where?
Ocean (70 % of earth's surface, depth 〜 4 km, salinity 〜 3.5 %)
Ice (mean depth 〜 2 km over Antarctica and Greenland)
Groundwater, soil moisture, ice in permafrost (not precisely known)
Lakes, rivers
Water vapor in the atmosphere
Can we discuss "conservation of mass of water"?  I have not confirmed.
Chemical reactions negligible? ... unlikely.
Chemical reactions macrospically balanced? ... likely.