Wastewater rhymes with:
whitewater, backwater, breakwater, bridgewater, bywater, clearwater, coldwater, deepwater, drinkwater, fitswater, fitzwater, floodwater, freshwater, goldwater, headwater, pinkwater, rainwater, sidewater, stillwater, tidewater, underwater, whitewater
Wastewater sounds like:
wachter, waechter, wagster, waster, waycaster, wechter, westair, westar, wester, westra, wooster