Toilet water pulsing in bowl

[brax71]

I tried to google this, but couldn't get the computer to understand the noises I was making nor could it see my arms waving to describe the problem


The water in the bowl of our powder room toilet seems to pulse and surge with an associated whoosh whoosh sound.  I can't figure out what's causing it or whether to worry, or how to fix. 

Details:
- No sewage smell and no sewage coming back into toilet (thank goodness)
- Everything that we flush goes down like normal
- 20 year old house
- Septic with mound (previous owner had the tank pumped in 2019)
- Well water
- I've seen other toilets in the house pulse (a very little) like this, but never this much/often/consistent
- Pulsing seems to come and go, but with no rhyme or reason that I can find
- Greater Tampa area

[Large Wooden Badger]

I second that - likely wind

[K. L. McReynolds]

Our first new house was on septic----never had that situation and our roof was the highest point for miles. That kinda seems to take the wind theory out. Our current home is on septic(built in 1965). Now and then, the master bath toilet gurgles---and makes a bloop-bloop sound. It is the fartherest away from the septic and is vented by a Schrader vent. That vent is probably partially compromised, since the bowl fill is often minimal.

Both bath toilets are Am. Std. Cadet 3(I think) models. The master is a taller model.

We've been in thi9s house 13 years and always had this issue---tank has been pumped three times. Once when we moved in, then three years later when a really rainy summer caused a backup, and two years later when a snow melt filled the tank. 

No odor after the bloop-bloop episodes, so no idea what is happening.

[MsNomer]

I think I’ve seen what you describe somewhere in Europe—with a little extra. One small t*rd kept disappearing and reappearing. It was so funny I videoed it.

[Stwood_]

I think I’ve seen what you describe somewhere in Europe—with a little extra.  One small t*rd kept disappearing and reappearing.  It was so funny I videoed it.

A good laugh at the end of the day is good for the heart.

[R Clark]

Our house is 16 years old, on septic system.

Breezy winds cause pulsing in the bowls, although we have no "gurgle" sound until the toilet is flushed.  On days like today (winds gusting to near 50 mph), the water level in the bowls is very low as water has been siphoned out of the by the wind blowing across the vent stack outlets.

Do you notice this more during periods of windy weather?

I think the severity of the effect depends on the exact configuration of the specific house.

I vote for wind as the causal effect.  You don't smell sewer gas when the path opens up because the gas isn't moving from the septic to the bathroom.  Rather, it's the other way around as the pressure inside the house is higher than outside (in the vent stack), and so "bathroom air" is going "down the drain" rather than sewer gas coming up.

I wouldn't worry about it.

[Bach]

Pressure tank bladder or leak in pressure tank.

[DogwoodTales]

Curious- How could that be the pressure tank? I know about such tanks to pressurize the water from a cistern or well. Is there some such tank en route to a septic system?

Better yet how is this problem avoided?