  In this article, we extend an argument of Vogtmann in order to show homology
stability of the Euclidean orthogonal group $O_n(A)$ when $A$ is a valuation
ring subject to arithmetic conditions on either its residue or its quotient
field. In particular, it is shown that if $A$ is a henselian valuation ring,
then the groups $O_n(A)$ exhibit homology stability if the residue field of $A$
has finite Pythagoras number. Our results include those of Vogtmann, and hold
with various twisted coefficients. Using these results, we give analogues for
fields $F\neq\mathbb R$ of some computations that appear in the study of
scissor congruences.
