We have a septic tank. Our house about 35 yrs old. I've noticed the past couple days our toilet in out master bath has been mysteriously empty when I go in the room. We have 2 bathrooms, back to back. Today I took a shower in that bathroom and heard "bubbles" and noticed the toilet water level going down while showering. Do we need to have our septic serviced? Was last serviced 5 yrs ago.The yard where the tank is odor free and dry. There is no odor in the house. We live in South Florida. Thank you!

Wonder if roof vent is clogged?

Run some water down your vent pipes on the roof. Your shower needs air to drain.. Sounds like it is draining your commode to get air.. Stephen let me know if this helps...

Flushed both toilets simultaneously then ran hose down vent pipes. Problem seems solved. Thank you!

ADDENDUM
Well the septic tank needed attention. The problem ended up being toilet paper in the pipe backing up and slowing the flow of water. We have now switched to a septic friendly TP. And have a clean as a whistle tank!! The septic guy showed my hubby how to clean the line if this should happen again. Thanks for all your help!

Let me give youa few "septic tank tips" to keep your system running smoothly.
Since the septic tank is such an essential part of a sewage system, here are some points to remember about the "care and feeding" of that part of the onsite sewage treatment system.
A "starter" is not needed for bacterial action to begin in a septic tank. Many bacteria are present in the materials deposited into the tank and will thrive under the growth conditions present.
If you feel that an additive is needed, be aware that some may do great harm. Additives that advertise to "eliminate" tank cleaning may cause the sludge layer to fluff up and be washed out into the drainfield, plugging soil pores. Some additives, particularly degreasers, may contain carcinogens (cancer-causing) or suspected carcinogens that will flow into the ground water along with the water from the soil treatment unit.
Send all sewage into the septic tank. Don't run laundry wastes directly into the drainfield, since soap or detergent scum will plug the soil pores, causing failure.
Normal amounts of household detergents, bleaches, drain cleaners, and other household chemicals can be used and won't stop the bacterial action in the septic tank. But don't use excessive amounts of any household chemicals. Do not dump cleaning water for latex paint brushes and cans into the house sewer.
Don't deposit coffee grounds, cooking fats, wet-strength towels, disposable diapers, facial tissues, cigarette butts, and other non-decomposable materials into the house sewer. These materials won't decompose and will fill the septic tank and plug the system. To use a 5-gallon toilet flush to get rid of a cigarette butt is also very wasteful of water. Keep an ash tray in the bathroom, if necessary.
Avoid dumping grease down the drain. It may plug sewer pipes or build up in the septic tank and plug the inlet. Keep a separate container for waste grease and throw it out with the garbage.
If you must use a garbage disposal, you will likely need to remove septic tank solids every year or more often. Ground garbage will likely find its way out of the septic tank and plug up the drainfield. It is better to compost, incinerate, or deposit the materials in the garbage that will be hauled away. As one ad says, "You can pay me now, or pay me later."
Clean your septic tank every 1 to 3 years. How often depends on the size of the tank and how many solids go into it. A rule of thumb is once every 3 years for a 1,000 gallon tank serving a 3-bedroom home with 4 occupants (and with no garbage disposal).
Using too much soap or detergent can cause problems with the septic system. It is difficult to estimate how dirty a load of laundry is, and most people use far more cleaning power than is needed. If there are lots of suds in your laundry tub when the washer discharges, cut back on the amount of detergent for the next similar load. It's generally best not to use inexpensive detergents which may contain excessive amounts of filler or carrier. Some of these fillers are montmorillonite clay, which- is used to seal soils! The best solution may be to use a liquid laundry detergent, since they are less likely to have carriers or fillers that may harm the septic system.
Each septic system has a certain capacity. When this capacity is reached or exceeded, there will likely be problems because the system won't take as much sewage as you want to discharge into it. When the onsite sewage treatment system reaches its daily capacity, be conservative with your use of water. Each gallon of water that flows into the drain must go through the septic tank and into the soil absorption unit. Following are some ways to conserve water that should cause little hardship in anyone's standard of living:
Be sure that there are no leaking faucets or other plumbing fixtures. Routinely check the float valve on all toilets to be sure it isn't sticking and the water isn't running continuously. It doesn't take long for the water from a leaking toilet or a faucet to add up. A cup of water leaking out of a toilet every minute doesn't seem like much but that's 90 gallons a day! So be sure that there is no water flowing into the sewer when all water-using appliances are supposed to be off.
The most effective way to reduce the sewage flow from a house is to reduce the toilet wastes, which usually account for about 40 percent of the sewage flow. Many toilets use 5 to 6 gallons per flush. Some of the so-called low water use toilets are advertised to use only 3.5 gallons per flush. Usually the design of the bowl hasn't been changed, however, and often two flushes are needed to remove all solids. That's 7 gallons! Toilets are available which have been redesigned and will do a good job with one gallon or less per flush. Using a 1-gallon toilet rather than a 5 gallon toilet will reduce sewage flows from a home by about a third. This reduction may be more than enough to make the sewage system function again. While prices may vary, 1.6 gallon toilets can usually be purchased in the $200 range, far less than the cost of a new sewer system. Baths and showers can use lots of water. "Setting up camp" in the shower with a shower head flow of 5 gallons per minute will require 100 gallons in 20 minutes. Shower heads that limit the flow to 1.5 or 2 gallons per minute are available and should be used. Filling the tub not quite so full and limiting the length of showers will result in appreciable water savings.
Is the water from the faucet cold enough to drink? How long do you let it run to cool down? Keep a container of drinking water in the refrigerator. Then it won't be necessary to run water from your faucets in order to get a cool drink.
There may be other ways to conserve water that you can think of in your home. The main idea is to consider water as a valuable resource and not to waste it.
Following a few simple rules like not using too much water and not depositing materials in the septic tank that bacteria can't decompose should help to make a septic system trouble-free for m, too! Any years. But don't forget the septic tank does need to be cleaned out when too many solids builtreatment system.
With a water meter you can determine how much water your automatic washer uses per cycle. Many washers now have settings to reduce the amount of water used for small loads. Front loading washers and suds savers use less water than top loading machines. If your sewage treatment system is reaching its maximum capacity, try to spread the washing out during the week to avoid overloading the sewage system on a single day. Septic tanks need tender, loving care too. Good luck, Tom