We report on an investigation of the electron-hole (e-h) plasma decay time tau(tot) versus e-h pair density in semiconductor quantum wells. We determine the density reached in a steady-state photoluminescence experiment from the optical spectra and compare it with the e-h pair generation rate. We find that in our samples only radiative e-h recombination is important, and that nonradiative processes and plasma expansion have negligible effects on tau(tot). At plasma densities larger than 5 x 10(12) cm-2, we observe a strong nonlinear reduction of the e-h capture rate into the quantum wells.