I live in a small town in S.California,Norco,also known as horse town U.S.A. A neighbor up the road farms rabbits;many thousands of rabbits and even more droppings. Lucky me! FREE!I have been composting this stuff for years. I make circular bins approx 42 inches in diameter and 42 inches high out of galvanized 2inx4inx42inch wire fencing which I wrap with shade cloth And then wrap with 1in x 1in plastic fencing. All materials available at your home improvement warehouse. The manure is bone dry when I fill the bins.To wet the manure I coil a piece of soaker hose on the top and when water starts to come out the bottom I cut the water & cover the bins with shade cloth and a piece of plywood. Within 36 hours or so my thermometer starts to take off, getting to a little over 150 degrees F. After a few days I use a 5/8 in stainless steel rod to poke holes all the way to the bottom and +/- 6 inches apart this allows the pile to get air. I watch the temp and the moisture content daily and when the temperature drops to about 100F and the pile is just moist and has lost 12 inches off the top I remove the cage. Not easy. Break up the pile and spread it out +- 6-8 in thick, on top I spread out this weeks lawn cuttings and an equal amount of dry grass saved from dethatching the lawn in January. I mix all this together along with any kitchen scraps.The whole lot then goes back into the bin and each 8-10 in layer is lightly watered. Within 48 hrs it is cooking again and when it cools I repeat the process I do this about 4 times and then leave it to mature, just keeping it moist. Finally it is transferred to 5 ft diameter bins to await use. I start usually in March and have three bins going simultaneously. Not bad for a 67 year old guy. It really is so much better than ANY bought stuff you should taste my vegetables. I hope this is help full to a few people.

It took me 3 years to train mine into a 6-foot tree form and it died this winter. :( Oh well, but back on topic ... sometimes the flowers smelled really sweet and grape-like and sometimes they smelled like cat urine. Go figure. If I remember correctly, they smelled sweeter and more pleasant when they were young and began to smell poorly as they aged. This year I'm going to try again to form a Wisteria standard, but I'm using Wisteria macrostachya 'Blue Moon'. It's supposed to be more hardy, but like Amethyst Falls it's not crazy aggressive. Also, the flower panicles are longer (about 1 foot) and it supposed to repeat bloom at least 2-3 additional times through the season. Wish me luck!

Heater vents and switch plates do not emit sewer gas or urine smells. I would suspect a dead animal behind the walls. That can give off sweet almost urine type odor in the later decomposition stage. It's time for you yourself to crawl under the house and use your nose to find the center of the issue.

The post does not say where you live so I cannot tell which plumbing code you are under, however this house is new to you and if you are under the IRC (International Residential code) or the IPC (International Plumbing Code) there is a very strong likelyhood that you may have an "AAV" (air admittance valve), AKA "Studor Vent" or "Cheater Vent" instead of a true vent pipe in your bathroom. One quick way to get an good idea if you have an AAV is open the cabinet under the sink when you smell the odor. If you have a defective AAV the odor should be much stronger under the sink. AAV's have a spring loaded plunger that will allow air to enter the drain line to prevent a negative pressure that would suck the water out of your traps, but, when working properly they are closed to prevent sewer gasses from escaping from the pipe. Given that it is a mechanical device, it also stands that it is subject to malfunctioning. AAV's must be installed at a location where they can be periodically inspected and allow access for repair. Typically for a bathroom they are installed on the lavatory bowl waste arm in the cabinet under the sink. Look at the sink drain line. If you have an AAV you will see a Tee fitting on the horizontal line coming out of the wall and before it connects to the P-trap from the sink bowl. You will then see a vertical line attached to that tee which rises a minimum of 6" above the horizontal line and generally it will rise up behind the sink bowl. You will then see a Cap on the top of the line, but if you look close you will see either some slots or a square opening on that cap fitting. That cap fitting is the AAV. AAV's are mounted by means of ordinary pipe threads. On the top of the vertical riser there is a female thread adapter and the AAV is simply screwed in. To replace it you simply unscrew the existing AAV, than apply teflon tape to the threads of a new AAV and screw it back in place. You can get the AAV's at any hardware store or home supply center. Personally I prefer to go to a True Value or ACE hardware and you will be more likely to find a clerk that really knows what their talking about to help you.