Abstract: An aftertreatment system comprises a reductant storage tank and a SCR system including a catalyst for reducing constituents of an exhaust gas. A reductant insertion assembly is fluidly coupled to the reductant storage tank and the SCR system. A controller is communicatively coupled to the reductant insertion assembly. The controller is configured to: determine an initial pressure of the reductant, determine a first pressure at which the reductant is to be delivered to the selective catalytic reduction system and adjust an operating parameter of the reductant insertion assembly. The adjustment of the operating parameter results in an at least selective delivery of the reductant at the first pressure to the SCR system.