You have ants in the toilet tank? Or something else with the ants?

Do you have municipal water or well water?

If there is green in the tank, it could be alage, mold, minerals depositing, copper pipes leaving tarnishes... what is the green stuff in the tank? It's probably on the tank surfaces and not in the water since your bowl water is not discolored.

I would pour a bit of bleach in the tank, let it sit for a bit and then flush. Might help to use a toilet brush to dislodge some of the "mold". Repeat with the bleach if necessary.

For ants, get the Terro Liquid Ant Bait traps.

Is this a less used guest bathroom?

You have ants in the toilet tank? Or something else with the ants?

I think they may be coming up from around the bottom of the toilet where it connects to the floor, but I'm not 100% sure. A few weeks ago they were coming from behind the baseboard, then all of a sudden then disappeared; now they're back again. They're crawling up the sides of the toilet, up under the seat and some of them are heading towards the tank; most are on the sides and bowl rim. Earlier in the week I bleached the bowl, and I cleaned everything again yesterday (except the tank - I don't think I've ever done that), and they're still coming, there seem to be even more today. I can't figure out what's attracting them. Anyway, I ran into town this morning and got some Terro traps from the grocery, hopefully that will knock them out.

"Do you have municipal water or well water?"

Well water; softened and treated to remove iron. I'm not sure what the green stuff in the tank is -- I took one look and quickly put the lid back on. I was kind of shocked, I've never seen that before. Yuck. I'm going to have to act my age and deal with it...

"I would pour a bit of bleach in the tank, let it sit for a bit and then flush."

I'll try that to see what happens. If it's enough to get rid the water color back to somewhat close to normal it won't so icky to go in there with a scrub brush and knock things down. Yuck.

I looked this up under green water in toilet tank and got a youtube on how to clean the tank with will horrify some since we had a long acrimonious thread on the subject. Vinegar and Baking soda. You empty the tank by turning off the water and flushing, pour in a quart or moreof vinegar and let it set for an hour. Then dump in some baking soda to help loosen any goo and turn the water back on and flush a couple of times. The vinegar changes the ph killing any bacteria (you arent going to get algae in the tank unless you have untreated water from some weird source) and the soda does all that fizzing and helps clean the unreachable corners. I use vinegar in my tanks from time to time because we have iron eating bacteria in our water table. Natural harmless but ucky brown slime. Vinegar keeps the parts from clogging up with this stuff. Bacteria is very susceptible to changes of PH and vinegar is much safer and not so hard on your toilet mechanism than the alternative bleach which is a base vs vinegar which is an acid. Anyway they suggest simply pouring in a cup of vinegar once a month or so will keep the issue at bay.Just pour it into the water in the tank and let it set.

This stuff worked wonders on our municipal water toilets, I wish I had had it when selling my parents’ house to try on their well water. Half a bottle in the tank, wait overnight, flush. That’s it.

You've gotten good advice about the tank...on to the ants. Sounds like you have moisture ants and they can be a sign of damp/rotting wood. It's possible you have a leak under/around the toilet seal and the floor is rotting. I would have a plumber or handyman pull the toilet and check...you might have to replace the floor (or part of it). https://www.thepestadvice.com/moisture-ants/

"Sounds like you have moisture ants and they can be a sign of damp/rotting wood."

Oh no! And highly plausible. The shower in the master bath is on the other side of the toilet wall and the shower isn't waterproofed correctly, we most definitely have big problems there....but not a big enough budget to gut the thing yet. It's a total rip-out.

Good tips on cleaning the tank. I set the ant traps out and accidentally spilled one of them on the bowl rim, so I left the spillage there because the ants sure did seem to like it -- figured I'd shut off the lights, shut the door and let them gorge themselves to (literal) death. I'll wait a few hours (hope they signal all their friends to the feast...) and then tackle the tank.

ETA: Holy Moly! I was curious and ventured back in there -- sure enough, there is now a small swarm of ants around the trap and on the toilet which seems to be growing by the minute. What the heck is in this stuff?!?

Good thing I have another bathroom. But I am going to have to clean it up tonite. Enter secret weapon "bug vac" I have on hand for this type of situation (bought it for the box elder bugs on the windows, works like a charm).

If the water's not green in the bowl, I'm betting on algae. I think white vinegar OR baking soda may work better than bleach on algae - along with a good scrub. Mixing them together would cancel out the strong acidity or alkalinity of either alone.

As for ants, I'd investigate to find where they're getting in and block that, then clean the area thoroughly, since they create scent trails. I've used caulk for blocking entry points, and rubbing alcohol to wipe away the scent trails. It's helpful to figure out what particular kind of ants they are as well.

I think the traps are borax with some kind of attractant. It eliminates the nest because they carry it back to all the residents and everyone is killed. But if they are there because of the moist conditions, they will eventually return.

Neglected to mention I've used those Terro traps and the liquid drops too. They work for awhile, but if you still have openings and things to attract them, they'll come back sooner or later.

Some ants ignore the bait completely tho, depending on their preferred food sources. IIRC the directions recommend mixing with some fat if that's the type of ants you have.

If the green water in the toilet tank is caused by copper pipes, you probably just need to flush more often. If it's algae, a bit of bleach and a scrub should do the trick. It's probably unrelated to the ants.

Catch some of your ants and look them up. Carpenter ants are big, black and destructive because they chew on wood. They look for damp wood. The solution is to make sure your wood is dry. Other big, black ants are attracted to foods. Tiny ants tend to be the same.

These are tiny brownish-black ants.

I’m a big fan of MaxForce products, available on Amazon. I came here last weekend and ants were swarming around a ziplock bag of dog food in my basement laundry room. I killed what I saw, and next morning it was worse. A steady steam of them from under the floor molding, along the wall to the front corner of the cabinet, up to the counter. I resisted the urge to kill them, put a drop of MaxForce on the back corner of the counter and a few drops in a trap on the floor. By the next day traffic had eased up a lot. I left the house, came back today and no ant in sight.

As for your bathroom water issue, I hope you can address that sooner rather than later. I know how hard it is, when you’re not prepared to deal with something. If you know where it’s coming from and the area can be sealed off from new intrusion without trapping moisture inside, I’d consider that. I’ve lived with duct tape and plastic sheeting shower walls!

Vinegar is acidic (pH<7), baking soda and bleach are alkali (pH>7). Their cleaning action when used alone results, in part, by having a pH that isn't neutral (not =7). Mix them together and they offset one another and become ineffective.

It's useless to mix vinegar and baking soda

Toilet flanges (the hardware that a toilet is bolted to) are often not completely sealed around the hole in the subfloors and floors they pass through. The toilet will cover any such openings around the flange so you can't look at it by looking from in the room, unless you lift off the toilet. If ants were also seen entering around the baseboards, then the ants are coming from under the floor and just happened to pop up by the toilet. Likely unrelated to the green color in the tank.

Was there an answer given about whether this is or isn't a frequently used toilet?

I'd bet on long term use of copper pipes for the green color, green algae may require light to grow and being the inside of a dark toilet tank isn't the best place. As for the ants, if there's a water leak then they might just be looking for water. I also recommend Terro liquid to get rid of the ants. It works best for me when I fill up a small bottle cap with Terro and let the ants slurp it up, refilling the cap as needed. Don't be alarmed to see a lot of ants initially, that's good, they'll go back to their nest and feed the queen with the Terro which in due time will kill them all. If you suspect a pipe leak, placing a water alarm behind the toilet would be a good idea, if the leak is in the wall you may need to check the crawlspace for moisture.

"Was there an answer given about whether this is or isn't a frequently used toilet?"

Daily use, but not heavy use.

Here is it a couple hours later and the swarm doesn't seem any bigger. Some have dropped into the toilet; a flush took care of that. I'll give it another hour or so before I vacuum them up, and clean up the bowl and rim well. I'll try dousing the rim with rubbing alcohol to kill off any scent trail and move the trap to back behind the toilet to keep the next round of them away from the bowl so I can at least use the toilet overnight :o/

If you have green water in the tank then you would have green water in the bowl. Are you saying the green water is only in the tank? The green watre would enter the bowl with every flush.

Don’t move the traps or vacuum up the ants. You want to let them take the bait back and share it with the colony/queen. It may take up to 2 weeks to kill the nest.

Terro also makes liquid drops that you can squeeze into any cracks where you see ants coming up.

Terro and fixing the water issue have successfully worked for me on a variety of ants both inside and outside.

Good luck!

porkchop, the thing about Terro and other similar products that don't kill on contact, is that you need to put up with their continued presence for a day or two. How these products work is that the ants are attracted to it, thinking it to be food, and take it back to the nest for others to feast on. It kills with a delayed action. Rinse and repeat a few times and ultimately (in theory) the colony all dies.

Insecticides like RAID etc that kill on contact do nothing about the much more numerous individuals in nests that are elsewhere.

Terro doesn't always work for me and sometimes I need to call my pest control provider to use their stronger (but still human and pet safe) professional agents to treat both the site where activity is visible and also a 360° treatment of the structure. What they use is also the "poisoned food back to the nest" type so patience to wait up to several days for the activity to end is required.

It will be fine to move the trap to where you see them coming in and cleaning up the area where they are now so you can use the toilet. It may be that they return to the toilet area for whatever reason they were attracted there in the first place, or they might just be attracted to the traps and skip the toilet.

Not sure what you were using to clean the toilet seat before all this, but if you were using a cleaner or sanitizing wipes that are lemon scented, that could be attracting them to the toilet seat.

I have had ants come into my kitchen, almost always in the spring. I went to our local hardware store and a very kind and knowledgeable man sold me Terro that is little packets of liquid that you cut the top off and stick it in the ground outside the house where the ants are coming in. It happened just a couple of months ago now and I went outside the house and could see the trail of ants heading up the house and in through the jalousie windows in the basement. It stopped them right away. Great stuff.

When is the last time you shocked your well? If you have anything in the toilet, algea etc then you have it in your entire system.

Update: Well, it's been just over a week. I read the advice above and let the bait and ants be (other than the ones that dropped into the toilet -- those got flushed). Have been very busy and finally got a day to get around to cleaning up. Sigh. Hundreds of dead ants in the traps, a few more trickling up from beneath the toilet. The spilled bait dried into a hard layer on the floor and part of the toilet at the bottom. Fortunately it did come off with some almost-boiling water and vigorous rubbing. I then swabbed down the whole toilet area floor with rubbing alcohol to kill off the trail (the ants coming up sure didn't like that and skedaddled). So that mess is finally cleaned up. For now. Will have to see if they come back.

I then emptied the tank and dumped 1 gallon of vinegar in there. It's soaking now. I'll flush later today and see what's what. I had to place an A* order so added the Instant Power tank cleaner to my cart just in case I need it; I can return it if the vinegar works.

Yuck. Just yuck. Once the tank is thorougly cleared of the whatever-it-is gunk, I will keep on top of keeping it clean. I had no idea you have to clean the tank occasionally.

Get some of the outdoor Terro traps and put outside in front of the house wall just behind your toilet. Trust me, they will find it!

I like the liquid Terro better than the traps. When I can only find traps, the ants sometimes will happily pass them by without going in. I always spill a bit of the liquid into their path to make it easier for them to find it.

The liquid does dry into a hard lump because of the sugar in it. As you discovered, if you put a hot compress on it (like a sponge or wash cloth) and let it sit there for 30-45 minutes, that will soften it to allow it to be wiped up without too much elbow grease. The good news is that Terro's ingredients are safe for human contact so it's not like you're cleaning up some kind of dangerous insecticide spill.

PS - As I mentioned before, I doubt that the ant problem is related to the toilet tank problem.

I was referring to Terro in a squeeze bottle and I explained why I don't like the trap format. You must have missed that. The company refers to that product as Terro Liquid. Click to enlarge

^^ Is the squeeze bottle stuff as liquid-y as the stuff in the traps? If I see it in the grocery I might pick it up, it seems like it would be handy to have on hand to dot around here and there as needed. The liquid in the traps spills very easily. I still have two traps left, if I need to put them out again I'll place them in a small throw-away plastic lid to contain the spillage.

As Sherry said, the Terro "traps" are plastic containers that you cut the tip off of and they go OUTSIDE the house, near wherever you see ants near the foundation. The traps are stuck down into the ground a little way.

" Is the squeeze bottle stuff as liquid-y as the stuff in the traps? "

I would say perhaps the same - it's thicker than water but perhaps a bit thinner than squeezing out white glue.

I find Terro Liquid much more useful than the traps. You can put drops here and there, directly on the paths they're following, and they immediately start feeding.

murray, what you've pictured is Terro Stakes, Those are different from the traps. What I was referring to as "traps", Terro calls "Indoor Liquid Baits". These can be used inside and outside, they look like this: (click to enlarge)

Take it off-line if you want to bicker over ant traps.

I removed my comments, except for the one about the outdoor traps, that work well with no mess, which started him. He needs to remove his.

Place a squirt of liquid Terro into a small bottle cap, place in/near the ant path, refill cap as needed, no mess to clean up, easy-peesy. To avoid a possible spillage, place cap on a small thin piece of cardboard with a couple of Terro drops on the cardboard to lure the ants to the cap.

Hope the ants clear up! I've done the vinegar in the tank thing several times (a cup or so in the water, didn't drain the tank) and I find it does help clean it. I've always heard that you shoulnd't put bleach into the tank as it ruins the components within.

We don't seem to need regular preventive insecticide treatments where I am. The "call the pest control service when Terro doesn't work" approach I previously described seems to be a once every 18-24 month event. We don't have a lot of bugs here and while a large ant visit is to be expected everywhere in my area, it's only an occasional thing.

One step the pros do that I don't have an interest to do myself is that they trace the ant trails until they find the nests. They use the same delayed action "feed the community what they share that kills them all eventually" stuff but by finding the nests, they're sure to treat those areas extra heavy so that the infestation ends. Until the next time.

Just as when Terro works, it usually takes a few days for the ants to be gone after the pro treatment.

We see this exact combo more often than you’d think, especially in older homes or cottages across the GTA and cottage country that rely on well water.

You've got two separate issues here, but they might be pointing to the same underlying problem.

1. The "Green Water" Mystery

If the water in the bowl is clear but the tank is green, it’s rarely algae (which needs light to grow). In Ontario, "green" usually means one of two things:

Copper Oxidation: If you have slightly acidic well water, it can eat away at your copper pipes. This creates a green "tarnish" (think of a copper roof or an old penny) that settles in the tank where the water sits still.

Iron/Sulfur Bacteria: Since you mentioned having an iron filter, you might have a specific type of harmless bacteria that reacts with your well's mineral profile, creating a green or "slimy" biofilm.

The Fix: Stick with the Vinegar method mentioned by Patriciae. It’s much gentler on your flapper and seals than bleach. Bleach is a base and can actually "dry out" the rubber components in your tank, leading to leaks down the road.

2. The Ants (The "Plumber's Warning")

Olychick hit the nail on the head. In our region, "moisture ants" are a huge red flag. They aren't looking for the water inside the toilet; they are attracted to the damp wood under it.

Since you mentioned the shower on the other side of the wall has waterproofing issues, you likely have a "moisture bridge" happening. Water is travelilng behind the wall, soaking your subfloor, and creating a buffet for those ants.

The Pro Advice:

Don't just bait them: While the Terro works for the colony, the ants are just the "symptom."

Check the Seal: Feel the floor around the base of the toilet. Is it soft? Does the toilet rock slightly when you sit? If so, your wax ring might have failed due to the floor shifting from that shower leak.

The "Paper Towel" Test: Dry the floor around the toilet completely. Lay down fresh paper towels. Flush a few times. If those towels get damp, your toilet seal is gone, and the rot is getting worse.

Verdict: Clean the tank with vinegar to help the "yuck" factor, but please consider having a local pro pull that toilet to check the flange. If the wood is rotting, no amount of ant bait will solve the structural issue. Better to catch a soft subfloor now before the toilet ends up in the basement!

Rosedale, is it possible to see the damage from the basement if the ceiling is exposed? Asking for a friend..............

murraysmom,

Absolutely - tell your "friend" that an exposed basement ceiling is actually the best-case scenario for troubleshooting this! If the floor joists and the underside of the subfloor are visible, you can play detective without tearing anything apart.

Here is what to look for when you're standing under that bathroom:

1. The "Tell-Tale" Stains

Look directly up at the area where the toilet drain (the large black or white pipe) passes through the floor.

Water Staining: You’re looking for dark, tea-coloured rings or "tide marks" on the wood.

Active Drip: Have someone flush the toilet a few times while you watch from below with a flashlight. If you see water seeping down the side of the pipe or dripping from the subfloor, the wax ring has definitely failed.

2. The "Soft Wood" Indicator

If the ants are indeed moisture ants, they are looking for rotted wood, which has a specific texture.

Take a screwdriver and gently poke the subfloor around the toilet hole. If the wood feels "punky" (soft, spongy, or crumbles easily), it has been wet for a long time.

Healthy wood will be hard and the screwdriver won't sink in.

3. Efflorescence or Mineral Deposits

Since you mentioned well water with iron and potential copper oxidation, look for white, crusty, or green "stalactites" forming on the wood or the pipe. This is a sign of a slow, long-term leak that has been evaporates and leaving minerals behind.

4. Tracking the "Moisture Bridge"

Since that shower is on the other side of the wall, look for dampness or staining that starts under the shower and travels toward the toilet. Often, the ants follow the dampest path. If the wood under the shower is dark but the wood under the toilet is dry, the leak is originating from the shower pan or drain and just "visiting" the toilet area.

Pro Tip: If the wood is dry right now but looks stained, it might be an old leak. Circle the stain with a pencil. Check it again after a week of heavy bathroom use - if the stain has moved outside your pencil mark, the leak is active.

It’s much cheaper to catch a $10 wax ring or a localized shower leak now than to wait until the subfloor needs a full replacement!

Rosedale, thank you so much for these very helpful tips. I can do most of those things pretty easily. I do not have well water but I do have water that leaves lots of deposits. That I am used to. Years ago I had the bathroom floor tiled. It had been linoleum. The guys took the toilet up and put it in the tub while they were working. They told that whoever installed that toilet, put it in a bit crooked and there was a tiny bit of moisture but nothing to worry about. My house was built in 1942 and I'm pretty sure the tub is from that time. The bathroom was enlarged by taking the closet from the second bedroom, years before I bought the house and they put a new cabinet for the sink. It's not a contestant for House Beautiful, but plenty serviceable and decent looking.

Anyway, thanks for the information. I really appreciate it.

Great information, Rosedele Pluming -- very helpful. Thank you!!