Lambda Aquarii is located at a distance of 365 light-years (112 pc) from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −10.5 km/s.

[6] The stellar classification of Lambda Aquarii is M2.5 IIIa Fe–1,[5] indicating this is an aging red giant star with an underabundance of iron showing in its spectrum.

This star is on the asymptotic giant branch and is generating energy through the nuclear fusion of hydrogen and helium along concentric shells surrounding an inert core of carbon and oxygen.

[18] On average, it is radiating nearly 1,600 times the luminosity of the Sun from the photosphere at an effective temperature of 3,702 K.[10] Hydor is from Greek Ὕδωρ "water", a name given by Proclus, according to Richard Hinckley Allen.

[20] Consequently, λ Aquarii itself is 壘壁陣七 (Lěi Bì Zhèn qī, English: the Seventh Star of Line of Ramparts.