Keeping water off tent's ground cloth

I recently tried out a big tent that I got for use when I camp out of the car. It is a Eureka Tetragon 9, a 9-foot, square tent. It was not a high-priced tent, but looked like it would work plenty well for my purposes.

Aware that tent floors wear out quickly if you place them directly on the ground, I brought along a 9X12, blue, plastic tarp, folded it to 9x9, and set the tent up atop the tarp. There was a downpour on day four, and I had a stream of water come down the hill behind my tent and run under the tent. It carried a layer of sand and mud which was deposited on top of, as well as under, the tarp. Having sand and mud between the tent floor and the ground cover defeated the purpose of using the tarp in the first place.

The edges of the ground cloth were tucked several inches under the edges of the tent. It was only a “hardware store” tarp, but even a custom ground cloth would be susceptible to over-flooding if there is a volume of water passing under the tent. Aside from more carefully picking my tent site, I wondered if p-netters have come up with a way to discourage under-tent flow.

I thought about putting a hem around the ground tarp, with .5” foam insulation rope sewn into the hem. That would provide a bit of a ridge that would encourage water to go under the tarp, not over, but I don’t think .5” is high enough, and any water that did get on top of the tarp would be trapped there by ridge on the tarp, so that doesn’t seem like a great plan. Pool noodles in place of the foam rope might be more effective at keeping water from the top side of the tarp, but if they were sewn into the tarp it will make it hard to fold the tarp. I guess they could be carried loose and just strategically placed under the edge of the tarp once the tent is erected.

I am curious to know if other campers have developed practical approaches to keeping water from getting on top of the ground cloth. What tricks have you discovered?

~~Chip Walsh, Gambrills, MD

tuck the groundcloth under
Mine is always no closer than 2" or so from the edge of the tent. It has never carried water, even in a three day soaker.

put the groundcloth
inside the tent.


which begs the question
…how do you keep the bottom of the tent dry?

Did you trench?
Some eco-nazis would be horrified at the thought, but a diversion trench at least on the uphill edge is an old Boy Scout solution; for moderate rain. You can back-fill it when you leave and make it look pretty good if you are careful. And, as you mentioned, look at the site and see if you can tell where the water runs during a downpour. Pitch your tent elsewhere. Or, buy a tent hammock.

Just the usual
I suspect you know about these, but I’ll mention them anyway, as I’ve given this a lot of thought recently, and others might benefit. I don’t have any special tricks for modifying the ground cloth to make it more of a bath tub. I’m just more careful with the standard stuff than I used to be.

I always buy the ground cloth that’s made for the tent, now, so that it’s tight with straps that go to the poles and just under the edge of the tent.

Seam seal the floor of the tent - optional.

I try to pitch the tent on ground that drains well and won’t be in the path of a streamlet in a long steady rain.

I keep a narrow shovel in my trunk just incase I have to dig a little trench to re-direct a streamlet. I never do it up front as it’s probably frowned upon, but have the shovel just in case. When I was a kid it was standard procedure to dig a V-shaped mote on the uphill side of the tent to redirect water in case of rain. I kind of doubt that the leave not trace ethic allows for that.

I don’t do this last one, but an option especially with a smaller tent is to hang a large tarp above the tent to give a large space of dry ground around the tent. This works especially well among tall trees. The trees act as tarp poles and also block the wind so that rain falls more or less straight down.


in addition to the rest…
All the previous suggestions work–especially the tarp and the trench. But since you usually can’t dig a trench (although if you do, fill it in the next day, and no one needs to worry about it), you can replicate much of the benefit of a trench with small logs that divert the water. A few length of birch are usually lying on the ground around here, and they can help keep water flowing away from your tent. Choosing the site well is a big help. If you’re camping in sand, you can definately do all the levelling and trenching you want to do.

Don’t know…

– Last Updated: Aug-21-07 6:36 PM EST –

Don't know all of your circumstances, but based on about 45 years of camping experience, the number one cause of water in a tent is usually related to poor site selection.

I personally use a ground tarp that is larger than the bottom of the tent I'm using. I place it under the tent. No portion of the ground tarp is left exposed once the tent is erected. I fold up any excess material & push it under the tent.

I have never had water (other than a few drips) inside my tent.....never.

The one time I did dig a trench, I dug it because I made a poor decision in site selection. If that situation were to occur again; I would make the effort to move the tent, and would not trench.

Saying that you will cover the trench is generally a cop out. The majority of people who trench around their tent do NOT cover it up before they leave. Even if they do; during a heavy rain storm much of the soil removed from the trench will have washed away, and all the soil that was removed is NOT, can not, be replaced. If the rain continues; even if you attempted to replace the soil before you leave, the softer soil will wash out of the trench after you've departed.

You trench around your tent.
The next morning the rain continues, but you make the decision to paddle on downstream.
You're going to stand in the rain & replace the soil in the trench you dug?
And it will look like it did before you dug the trench?

Additional options: Seam seal every seam on your tent; particularly those that may be stressed by the tension created by stakes &/or rainfly.

Spray your tarp with waterproofing.

Carry a small tarp which you place inside your tent, under your sleeping pad/bag.

If the tent bottom gets wet; at the first opportunity dry it before you use it again.



Poor site selection was my opinion

– Last Updated: Aug-21-07 8:06 PM EST –

as I read down the thread. No need to write it up now as Bob did a good job. I too have had water in the tent ONLY WHEN a poor site was selected. Good selection sure beats trenching which is not fun to dig!



Being Less Non Eco-Friendly

– Last Updated: Aug-21-07 8:27 PM EST –

Every one makes good points here, and Bob is right on the money. I have just one thing to add about trenching, even though we all know it's best to choose a site where it's not needed, and it's always best not to do it. If you do need to trench, you need not make it look like the trench everyone has seen examples of or heard/read about. Instead of excavating a trench that then must be backfilled, or as Bob says, thought about for a moment as you stand in the rain and then abandoned, try this.

Just insert the blade of the shovel and pry on the handle. This opens a slot in the soil, and that's all. Keep making these shovel-width slots end-to-end until the cut in the soil surface follows the path of the trench you'd otherwise have dug. This works every bit as well as a trench if you work carefully, and all you need to do to repair it is step on one side of the slot (the side toward which the dirt was pushed when you pryed on the shovel handle) and it closes right up. In some soils, you'd have a really hard time telling anything was ever disturbed afterward.

I've only had to do this a couple of times. Once as a kid in Scout camp, in very loamy soil, and once in a commercial campground in Colorado where the tent sites were just hard-packed dirt, but it saved the day without tearing things up in both cases.

While I was off fuming about all this trenching blather Bob covered it very well. But since I composed my thoughts a bit – here goes:

The sad fact is that trenching tent sites can cause land erosion which equals camp site degradation. These days there are just too many people trampling “wilderness areas” for such self-centered behavior as trenching tent sites to go unchallenged. This is especially true in areas with scant soil covers like the Pre-Cambrian terrain of the Canadian Shield/the ADK or the BWCA (among other areas).

Yeah, like so many others in my age group I learned to trench the uphill grade of tent sites when I was in Scouts several decades ago, but that was then. And in all due deference to my dear old Scout Master the fact is it was never a cool idea. Now with human populations at critical levels it’s more important than ever for people to be aware of the damage they are doing to our parks and forests when they act irresponsibly. There are many, many more people pressuring camping areas than ever before, heavy handed “landscaping” of tent sites is simply a bad idea. Not to mention the fact that it’s illegal to trench around tent sites in most State, National and Provincial parks.

I reject the idea that people who try to treat the earth with some respect or speak in favor of reasonable land stewardship are somehow “Eco Nazis”. What a depressing idea. …my two cents worth… - RK


Tent are consumeables . . .
. . . not family heirlooms. I find that waterproofing on the floor and fly flakes off after a few years anyway. I hardly ever use a ground cloth and my tents usually see about a month’s use a year. I can’t remember a tent of mine (mostly Eureka) that the floor was the first thing to fail.

your local eco-nazi

– Last Updated: Aug-21-07 9:19 PM EST –

Ok, I'll own up to being an "eco-nazi" and here are my thoughts.
1) Trench= evil.
2)Site selection was poor.

But then I got to thinking, hey its not this guys fault, there is something bigger at work here, soil compaction from over use. Every decent campsite you see has probably been used by every one else who has eyes. After a year or two of consistent use the ground becomes so compact that the water running on to it from that unavoidable hill behind you pools up instead of soaking in.

So how do we avoid this little predicament? If we camp in more hard to reach places we will only spread out our impact and the damage to plant life will most likely be worse than the alternative, plus who wants to walk that much further of the trail.

My humble suggestions are:

1: try a hammock. I got one years ago and neglected it for a few years until I went to Mexico and was taught how to sleep in one comfortably. Just remember to be nice to the trees

2: When you leave a site kick any leaves, sticks, etc back where your tent was. it is an easy habit to build and it will discourage more erosion and compaction. The organic material will break down into that light fluffy soil that will absorb the water and keep it out of your tent.

Wood (eco-nazi)

also for any other eco freaks/gear head. heres another idea for stressed campsites. A friend of mine introduced me to wood burning camp stoves. you can get them just as small as your gas burner and they run on scraps. great for places picked over for fire wood and great for long trips too, no need to pack tons of fuel bottles.


We went camping this last weekend
in our old Eureka Equinox. It has to be about 17-18 years old by now. We’ve had puddles underneath it, and no leaks. That wouldn’t be the case these days. The rainfly now has some tears. The floor has holes and the waterproof seam tape has pulled loose from the seams. Still, we had one rainy night and only a little dampness underneath luggage and such where the tentfloor was directly on the ground. Been a great tent for our family, but it’s time for it to retire.

Things that helped keep us dry…using a ground cloth (just a plastic sheet back then). Guying out the rainfly, tightly, to help shed the water and keep it away from the inner walls. Rainfly period. I don’t get these new single wall tents, at least no here in the Pacific NW. Keeping stuff away from the walls. Looking for well drained locations. Never did it myself, but I have seen others hang a tarp or dining canopy over the top of their tent.


I suppose
I misunderstood the question. I though the camper and his gear wanted to stay dry.


Car camping
Since this is a car camping type question, I’ll share my car camping method that ends (for me at least) the issue of wet gear, ground cloths, trenching, etc. I use a screened room with a full rain fly as a tent. Got it from Cabella’s a years ago. No floor, 7’ high, fly has long flaps that extend away from sides to shed water. I sleep on a cot, pack clothes in a few dry bags, room enough for a folding table, two cots and two chairs.

I can cook inside if it’s raining with the door open and sit comfortably to read at night. Cost was the same as equal sized traditional tents. No hassle at all about rain issues. One night in a long, heavy rain event, a streamlet of water passed through as I watched it from my comfy perch up on my cot. No harm, no foul.

Hennesey Hammock
Try one of these:

Otherwise - the suggestions to car camp and putting the tarp INTO your tent show merit and experience.

I personally opt for a good B&B with hot shower, warmed cognac, and a fireplace tended by the owner/manager. :wink:


I have not read much in this thread that sounds full bore linear eco-nazi. Common sense should supplement need. I like the birch log idea, but you won’t find anything remotely resembling “firewood” near car camping spots in the Rockies. OTOH, walk more than 100 meters from any campground and you will find plenty of dead and down stuff while people are paying $7 a bundle for split pine for campfires.

My impression of an eco-nazi is more extreme than the don’t trench mindset. (Trenching is usually unnecessary if you select a good site.) When you live and work near the Republic of Boulder you encounter the variety of e-n that preaches “look, but don’t enter.” They are in the process of closing open space lands to any kind of usage, even trail use, because we humans do not belong in the woods and will disturb anything more natural than a human. Excuse me? Is a human an alien to the Earth? It’s funny that most of the tax paid for open space they are trying to close conveniently forms buffer zones to isolate the wealthy estates from the unwashed masses. These particular lands have seen 150 years of human occupation from ranching to mining, railroad grade to stage coach, and a variety of other “human trespass.” There is very little virgin wilderness left in the lower 48 and I agree that it should be protected, yet carefully visited and enjoyed. It is perfectly natural for a human to be part of the woods. That human also has responsibility to be a beneficial caretaker.

What is your goal, really?
If your goal is to keep the floor of the tent generally clean, and dry, a groundcloth under the tent - in conjunction with proper site selection - should do the trick most of the time.

If your goal is to stay dry IN the tent, along with your gear, but the groundcloth INSIDE the tent, and be sure it is large enough to run a few inches up each sidewall.

This actually would be helpful for abrasion protection on the floor, since a lot of this occurs from inside the tent, with you and your gear being moved around. The groundcloth inside takes this abuse, and not your tent floor.

If you find out belatedly that you chose a poor site, and your groundcloth was under the tent, your weight will force any water that got between your tent and the groundcloth through the floor and into your gear, sleeping pad, etc. This will not happen if the groundcloth is inside the tent.

When I first read this method from Cliff Jacobson, I thought he was nuts. I am a believer now, having tried it in heavy rainfall. So what if the floor of the tent gets wet or muddy? It will dry, and must of the mud can then be brushed off.


I know this post is old but I may be able to help someone. We’ve always been able to dry our tents after a downpour but it was always our gear and beds getting wet that we didn’t like. The bed we used was just a 6" piece of foam it was a sponge needless to say. From then on we bought twin size waterproof fitted sheets (used for people who wet the bed) we put them on the bottom of our bedding to keep it dry and as for our gear we used 3 plastic totes, no water got in our gear and it kept things more organized. Hope that helps somebody.