A clog resistant in-line vortex emitter and drip irrigation assembly and method uses a double-sided circuit and a series of vortex chambers of optimized dimensions to create a pressure drop with large dimensions and good clog resistance. The vortex chamber 100 also al lows for a lower exponent than traditional circuits. This gives a pressure regulating property to the no-moving-parts circuit. The vortex emitter allows for some pressure regulation without sacrificing recyclability or requiring moving parts. The vortex circuit of the present disclosure is optimized for an emitter efficiency Ef value wherein Ef=(k/Ackt)*Amin such that k is a unitless head loss coefficient, Ackt is the area of the circuit, and Amin is the minimum cross sectional area of the circuit. A higher k per a given area with larger dimensions allows for a smaller part with a lower chance of clogging.