Table 1. Relative impact of various factors on phylogenetic and functional microbiome dissimilarity across samples (Adonis and Betadisp, permutation=999).

Factor	Phylogenetic			Functional			Samples
	R2Adonis	PAdonis	PBetadisp	R2Adonis	PAdonis	PBetadisp
Phase	0.246	0.001	0.001	0.087	0.001	0.001	All samples (n=427)
Sample location	0.124	0.001	0.001	0.055	0.001	0.003	All samples (n=427)
t	0.100	0.001	0.001	0.398	0.001	0.001	All samples (n=427)
T	0.172	0.001	0.003	0.194	0.001	0.003	All samples (n=427), influent was set at 20°C.
Water use frequency	0.039	0.001	0.039	0.021	0.005	0.040	Distal tap samples (n=348)
Pipe orientation	0.013	0.006	0.716	0.013	0.008	0.971	Distal tap samples (n=348)
Phase	0.311	0.001	0.001	0.104	0.001	0.001	Distal tap samples (n=348)
Rig	0.025	0.158	0.624	0.019	0.267	0.185	Distal tap at 5 months, 39°C (n = 70)
t (at 39 °C)	0.112	0.001	0.043	0.396	0.001	0.244	Control rig distal tap samples (n=175)
Phase	0.466	0.001	0.001	0.138	0.001	0.001	Control rig distal tap samples (n=175)
t (with elevated T)	0.249	0.001	0.015	0.513	0.001	0.398	Experimental rig distal tap samples (n=173)
Phase	0.256	0.001	0.001	0.084	0.001	0.001	Experimental rig distal tap samples (n=173)
Phase	0.126	0.001	0.098	0.104	0.003	0.069	Recirc. Samples (n=45)
Rig	0.124	0.001	0.003	0.072	0.016	0.962	Recirc. Samples (n=45)
t (at 39 °C)	0.444	0.001	0.730	0.681	0.001	0.519	Control rig recirc samples (n=27)
t (with elevated T)	0.759	0.001	0.687	0.608	0.001	0.807	Experimental rig recirc samples (n=28)
t	0.377	0.001	0.443	0.621	0.001	0.455	Influent (n=24)
Rig	0.041	0.001	0.039	0.012	0.011	0.053	Distal tap samples (n=348)
T (<51 °C or ⩾51 °C)	0.175	0.001	0.001	0.183	0.001	0.001	Experimental rig distal tap samples (n=173)

Both time (t) and water heater temperature setting (T) were treated as non-numeric factors. Statistical significance was set at 0.05: italic font indicates non-statistically significant.