A water heater pilot that won’t light may have a faulty thermocouple clogged pilot tube or gas supply issue. Clean the pilot orifice with compressed air to remove dust. Check that the gas supply valve is open. If the pilot lights but won’t stay lit replace the thermocouple which costs about 15 dollars. A faulty gas control valve may need professional replacement. Ensure adequate ventilation around the water heater. Never use matches if you smell gas.