Jenny brings up a good point CorporationsRule. Do you live in a High Rise or a Low Rise? Out West, here, the low rise apartments surrounded by landscaping are much more common than the high rises. Nevertheless, the highest I have seen anyone run a hose to the ground was seven stories in New Jersey. You have to use common sense in any installation like this. The tubing or hoses have to be clamped, wired or otherwise secured to the side of the building. In the case of the gentleman in NJ, he screwed several regular garden hoses together and because of the location of his balcony and the shape of the building he was able to run off the side of his balcony and around a corner into a sort of recess that ran up the building. This was not one of the newer, boxier types of buildings, so there were plenty of small projections that he could wrap wire around to keep the hose from banging in the wind. This was a few years ago, so as I recall, he went to apartments on the way down and asked if he could reach out the window and attach the wire to his hose. He grew great tomatoes and I'm sure his willingness to share helped him considerably. Many people simply find the downspout for rainwater and just drain into that. Depending on your building, the maintenance staff is often able to help figure out drainage issues. I have found that the ability to grow too many great tasting tomatoes greases a lot of wheels. Sometimes, if you are high enough, you can find some place to lead the tube that the wind will evaporate the water into small enough droplets that no one will notice.

Could be a problem in the leach field or pipes from the tank to the field. If you have a recent septic tank it might (should) have a filter at the tank output too keep solids from getting into the leach field. When those filters clog they restrict the water flow out of the tank and water can (will) backup into the home if the problem is not corrected. Those filters should be accessible through the cover at the tank output end and are usually attacked to a piece of PVC so they can be removed and cleaned. You can clean it yourself or call the septic company. Whatever the problem it must resolved cause replacing leach fields is expensive and you have to have the square footage available for a new field.

MrChuckles - This is a long shot I know due to the age of your original post. I had the exact same issue when I backwashed the filter this week. Backwash/rinse bubbled up out of drain in the deck and then out of the overflow into the pool. I assumed the line the backwash is plumbed to must be blocked/clogged and therefore back into other lines. I will be troubleshooting it this weekend, and would be interested in hearing more about the bad flap valve in your situation. Was this flap valve located in the multiport valve or elsewhere. I have a snake camera I am going to send down the drain line to see if I can see anything, but doubt it will be long enough. Worth a shot to see if you happen by chance to even see this.

Not a bad idea with one of those timers, might go that route. Don,t want to run the system off the barrel because every once in a while ill be putting some fertilizer in the 5 gallon bucket to be distributed for a day or two. I will try the one of those timers, just a matter of spending a few days to calculate the water usage.