I recently bought my first home that has septic, after 26 years of living with sewers. I've heard that putting lots of water down the septic all at one time is bad for the system, but I'm confused as to why. As I understand it, the septic tank pumps liquids and other broken down material into the leach field, so the water should go right through into the field.

Due to a chronic pain condition as a result of a car accident, I routinely take 2 hour hot showers to help be able to use my neck for an entire work day. With a standard shower head, this means I'm running about 250 gallons of water through the septic system. (And a low-flow showerhead isn't going to get me the pressure I need to help with my neck.) From an environmental standpoint, I'm not too concerned -- after all, I'm basically pumping the water out of my well and putting it back into the ground 100 ft away in the backyard, so the ecological impact shouldn't be too bad -- but I'm worried I'm somehow damaging my system.

Is this going to hurt the septic system? If so, is there something I can do (perhaps by modifying my plumbing and doing something else with shower waste water) to avoid damage?

  • I should note that I've been living here now for about 6 months and the showers haven't been an issue. I'm not trying to cure a problem I know about, but rather trying to avoid some future issue that I cannot detect. – David Pfeffer Jan 8 '14 at 12:32
  • My septic didn't mind 4 people taking 30 minute showers, or sometimes 6 or 7 people taking showers. You might want to put an envelope of "septic bacteria" down the toilet every month or two - it might be just a placebo but it won't hurt and if the showers are diluting your bacteria it might help. – Kate Gregory Jan 9 '14 at 1:37
  • The bigger issue might be the well. That's a lot of water used in a shower, and may run the well dry if a long enough drought happens. There are low-flow shower heads that have good pressure; I have one. That, or shorter showers, are the only things you can do to protect both the well and the septic system. Note that you aren't really taking water out of the well and then putting it back into the same place, the water spreads out and may hit other underground water instead of the one from which you draw. – poorplanning May 6 '18 at 3:20

It is similar to changing the water on a tank of fish, not quite but the best comparison I think of on the spot. Your septic system works by natural decomposition aided by bacteria, surprising similar to your stomach. Putting that much water into a septic field at once can disrupt decomp process by "shocking" the system or flooding/shaking it and moving the bacteria away from their food source. There are companies and even apartment complexes using septic so it all depends on the size of your system and if/how much you feed you system bacteria (there are quite a few products for this). If you find yourself needing to pump out your septic too often, or at all depending on the system, then I'd look into supplementing it with some products.


The only problem I could foresee is an over-saturation of the ground, where it will not take on any of the effluent that it is designed to do. If you have been there for 6 months and do not have any signs of problems at the leaching field, there should be no issue. Leaching fields are supposed to be designed for the amount of bath tubs and sinks in the whole house that are dumping into it.

I have had septic all along for the past 24 years and no issues with mine. I do not run a large volume through it, there are just 3 of us here. It is a 1989 house, with 3BR and 1 1/2 bath. Looks like yours is handling it well, if you see no issues outside.

Water on its own will not do anything to it. Its what goes down with the water that will, I mean cooking grease or oil, which is the worst, and non-biodegradable items. Do not use a garbage disposal with a septic, although, I have helped build houses where the owners MUST have a disposer, by their request, then they will need to be committed to pumping it out on occasion, since to a degree, it is acting as a holding tank.

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    I grew up in a house with a septic system. We used the garbage disposal all the time. Right or wrong, we credited the garbage disposal for the life of the system, which needed no maintenance for over 25 years. The veggies and orange peels, we surmised, introduced more micro-organisms into the system. The system was no match for eminent domain, however, which removed it to build a parkway. I think the #1 enemy to septic systems is washing machines. – Edwin Jan 8 '14 at 16:39
  • Good points, and a testimony to garbage disposals VS. septic tanks. This will be brought up when this issue rises during construction meetings. I have always had to maintain, no disposer on septic, with the company I had been with for 22 years, I was never told if it was based on actual experience or just an assumption. – Jack Jan 8 '14 at 23:10
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    Given that Insinkerator makes a special septic garbage disposal, which is 100% identical to a non-septic unit other than discharging a bit of septic enzyme every time it is run, I would assume they're fine. – David Pfeffer Jan 9 '14 at 2:28

I built my house in 1990 and to date there's never been any issuses with my septic tank and no pumping it. I don't believe in the ads saying it should be pumped every five years since it just takes away all the good stuf then you need to build up a new food supply and the proper amount of bacteria all over again and I have 2 baths a day since my car accident in my Jaccuzzi tub to allieviate pain and still no issues over the past three years. Since the water going down the drain is fairly hot as it enters the primary tank about 6" from the barrier to the secondary, I'm fairly sure most just flows over and when flushing the toilet, I think the solids sink anyways and the food drops where it should plus I add an activator every couple of months to keep the bacteria levels high.

For those who don't use their place much like cottages and a shop that doesn't get much food, I don't think enough food for the bacteria and the bacteria dies off and unless you keep adding activator, the septic can't work as it should. For the life of me I see nothing wrong with a garbage disposal as long as it just food being ground up as it goes down and one of the biggest things is a really great leaching bed.Mine was done in an old gravel road on top of course aggrigate that drains really fast, so I doubt I'll ever see troubles but if it's in more of a clayish area and water can't get away using lots of excess water would make the whole system into a semi holding tank in it's own way.


Its called hydraulic overloading in the septic business. Your system is designed to do a certain g.p.d (gallon per day). Most hones are designed off a 500 gpd rule which is homes under 2500sqft. If you are showering for 2 hours and in those 120 min lets say you use 2 gallons a min in the shower you have used 240 gallons capacity for the system for that day. Now remember the average person uses 50-70 gallons of water a day. That's toilet, laundry, shower, washing hands,drinking water etc. So if there are 5 other people in the house you have to take that into account.Also just because its rated for or designed for 500 gpd doesn't mean you should run it at 500 gpd. A car will do 6000 rpm but run it at that for a month non stop and tell me what happens. same principle.


Too much water washes the soil on to the leach field where it blocks it up. The longer the water and soil sits the better it settles or floats depending on what it is. Only the water would get out into the leach field in a proper system unless you run too much water too fast. The thing to do is to run your shower water outside into it's own drain area, but it may not be allowed where you are. Used to be called gray water system. Look it up.


Two years ago I bought a house with a septic system that had not been cleaned out in thirty years. When it rained, the yard smelled like a cesspool; it was nasty. Apparently, the leach field lines and tank were so full, when the guy pumping it out emptied the tank, the lines emptied right back into the tank and refilled it. It took three loads out to get it down near the bottom: neither cheap nor pretty.

My experience so far is this: if I wash too many loads of laundry, my yard will get "squishy" as my grandkids say. It will begin to smell. I suspect that I am forcing the gunky stuff into my yard out of the septic tank before it has had a chance to break down. My son has a new septic system and has no problem with his water load...as long as he has enough grass cover to keep excess water from setting off his septic alarms. It may depend entirely on the age of your tank and if it has all of the new bells and whistles or not.

  • This sounds like an improperly designed septic tank. The tank shouldn't let effluent into the field until it is actually liquid. – David Pfeffer Mar 11 '17 at 15:53

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