Shower water temper...
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Shower water temperature: how does it affect the worms?

New Member
Joined: 2 years ago
Posts: 1
Topic starter  

Hi everyone,

I first heard about this system 3 years ago and wanted to build one since; I went to a workshop with Wendy as a teacher and I understood how game changing a Vermicomposter could be. So thanks Wendy to share your knowledge with us. 

I've just finished building my system: 2 toilets, 1sink and 1 shower going into 1 IBC tank.

Now, somehow, I had in mind that a shower could be hooked to the system as well. And, I've been looking through these pages and couldn't find more info about how a shower's hot water would affect the worms.

That water is over 35°, at least, which is higher than what worms can take.

In my case, there's not much distance between the shower and the tank (my tank is one level lower than toilets and shower; almost under the shower). Not sure if that short distance can cool the water enough.

Are the worms buried enough it doesn't affect them?

Was I completely wrong about the shower?

If so, anything I could do to make it work?


Thanks a lot on advance for your answer(s) and your help.

Francois Cramer 

New Member
Joined: 8 months ago
Posts: 2

Hi Francois,

How did you go with the shower water connecting to the IBC?

I am designing a similar set up where the shower is only 1 meter away from tank. Does the temperature of the water affect the worms?

Thanks, Kit

New Member
Joined: 3 weeks ago
Posts: 1

Hi Francois,
I too have a sink, toilet and shower going into my IBC, and.I.was.xoncerned aboit water.temperstures as my.wife takes very hot showers.
I am not yet convinced that shower water cannot be handled well by the Vermi system, but as I see it, why cross-contaminate more water than necessary if it may be easily diverted?
One day I will likely divert at least our shower away from the IBC.
My system has been going for two years now, I believe.
It was without issue until about six months ago, when it was clogging intermittently, and I had to intervene and offer the worms some "islands" of cardboard egg cartons to help them survive the deluge. I and  I'm working now on troubleshooting.

One thing you might try to moderate water temperatures is to insert a septic basin or tank in the line between the shower/sink only, and the IBC. Not the toilet(due to solids).
As I see it, water from a hot shower would temporarily collect there, allowing the effluent to cool, until the next shower pushes/mixes the cooled contents along to the IBC.
I have a 40-60 Liter basin in mine, where I also have a macerating sump pump(more later). These basins are the type used in a basement to catch sewage and greywater to then be pumped above ground or to a city sewer system or septic tank.
I'm just suggesting the basin, not necessarily the pump, and for the shower/sink effluent only, not the toilet(due to solids).

I had wanted to try the macerating pump to reduce excrement particle size, which it certainly does; 50% ends up about pea-size. I wanted effluent to distribute evenly over the compost heap/wood chips/worm mass and the pump insures this, along with strong transit assist of solids.
I think most people(I did) underestimate how well poop slides down a wet plastic pipe, and I had thought I might NEED to pump to get the flow to the IBC 50-60 meters away; as it turns out, the pump is probably unnecessary and possibly problematic, as I have clogging in my IBC below the wood chip layer or at the interface of the wood chips, shade cloth filter, gravel layer before reaching the IBC outlet.
I am currently trying to troubleshoot my system.

I'll stop here and maybe find the right spot in the forum to detail my overall setup, variations from the prototype, and our experiences so far,

In short, you might consider STORING/MIXING your shower water to moderate its temperature on the way out.
Or, more simply, plug your tub/shower and let water collect right there and cool before you release it.


Eminent Member Admin
Joined: 6 years ago
Posts: 36

François and everyone! So sorry - I don't know how I missed the original post as I've only just seen this thanks to the latest one.

I really don't advise anyone to take grey water (shower, bath or kitchen) through a worm tank. Nor attach more than one toilet. It's too much for a 1m³ tank. Bear in mind that you have a natural ecosystem in an unnatural containment situation so it's consequently unable to regulate itself. If you introduce stressful conditions (a lot of water, a lot of water at temperatures approaching fatal for worms, macerated solids, etc) then you're placing your system under stress. The more stress you introduce, the more likely you are to experience problems.

Worms and their associated detritivorous ecosystem evolved to turn what would naturally end up on the surface of the soil - fallen leaves and fruit, dead vegetation, animal faeces, dead animals, etc - into soil. They create a free-draining but moist and moisture-holding environment with a lot of air spaces. The closer you can get to mimicing its natural conditions and state, the more likely it will be that your tank ecosystem will remain stable and unstressed.

François what you won't have seen in the original course you came on - and possibly not subsequently? - is the amendment I made to the design to improve drainage and aeration. It's detailed on the Design and Construction page. I added this after finding that water could sometimes get held up in the tank if the organic material wasn't well mixed enough and (most commonly) a bunch of fallen leaves added had created a membrane-like layer somewhere.

As for the grey water, the simplest and easiest solution (if you have the land and suitable climate) is to take it straight to mulch pits (pits containing the same sort of organic material you put in a worm tank) in the landscape. All mine goes to mulch pits uphill of trees which benefit from the nutrients and irrigation. Those mulch pits will attract the biology necessary to clean up the water. If you can't make use of the water in this way, then a soakaway/leach field-type arrangement may be preferable.

Wiggler, I would ditch the pump. You don't need to reduce particle size in the solids. In fact, it's much better if you don't. Spreading macerated solids right across the surface of the tank massively compromises essential aeration of the top layers, puts huge stress on the ecosystem and increases the chances of sludge making its way down through the organic material to clog the lower layers. Ideally, by the time it gets to the bottom of the tank, the liquid component of the waste should be pretty much clean.

I now have 3 worm systems on my site, one for each of 3 toilets. The oldest is 8 years (though we had to dismantle and rebuild in 2017 after wildfires burnt off the top of the tank). They cope with a large variation in numbers of people throughout the year and all are doing well. Our local education project also built one and they have 50 kids plus staff using it 3 days a week during term times. That one is also (amazingly, even to me!) doing fine. The single most useful thing I've found to keep in mind when designing in and around your tank is the principle of biomimicry already mentioned (in italics) above. Good luck!