Can a Hot Tub Sit on Gravel? (How-To)

When buying a hot tub, one of the hardest things is to choose its base. There are a lot of options, and one of them is gravel. So, can a hot tub sit on gravel?

Yes, a hot tub can sit on gravel. Gravel is strong enough to hold the weight of the hot tub. But, the gravel should be leveled before you place the hot tub.

There are a lot of different gravel types you can use, and much more to know about this. Down below we explain all the things you need to know.

Is Gravel a Good Base for a Hot Tub?

Yes, gravel is one of the best hot tub bases. Gravel is easy to set up, doesn’t cost a lot of money, and has a lot of advantages that other bases don’t have. 

When buying a hot tub, most people think that you don’t need a strong base. Hot tub when empty doesn’t weigh a lot, which makes people think that a weak base or no base will do. But, once you fill it with water, the hot tub will weigh 4000-5000 lbs. Can a weak base hold the hot tub? No, it can’t.

So, why choose gravel? Gravel is strong enough to hold the weight of the hot tub, doesn’t crack (like concrete does), and you can easily set it up.

It will take you less than 3 hours to completely make a gravel base for a hot tub. Unlike concrete that takes up to 28 days. One of the best advantages gravel has over concrete or deck is that you can drain the hot tub on gravel. Hot tub water won’t do any harm to gravel, and the spaces between tiny pieces of gravel will reduce water accumulation.

Just like any other hot tub base, gravel should also be leveled. When gravel is leveled it won’t allow the hot tub to move due to its tiny pieces. That will make your hot tub experience comfortable.

Having un-leveled gravel will make the hot tub experience uncomfortable, and eventually, it will crack the hot tub shell. That’s because the water will stress only one side of the hot tub.

Gravel will also make your backyard look better. After you level the gravel, you can pick decoration gravel to make the whole area look good.

Related Read: Does A Hot Tub Have To Sit On Concrete?

How Much Does It Cost To Make a Gravel Base for a Hot Tub?

The price you have to pay for a gravel base depends on your hot tub size. A 6-8 person hot tub is usually 80-90 square feet large. Building a gravel base for a 90 square feet hot tub will cost you approximately $70.

Gravel costs $0.70 per square foot. For a 90 square feet hot tub, you would need a 100 square feet base. So, 100 x $0.70 = 70$. Except for the hot tub base, you also need a few more inches of gravel around the hot tub. That’s because you want the water splash to get into gravel and not into your grass. Plus, it looks better.

So, you can build a gravel base for a hot for less than $100. It will also take you less than 3 hours to have it ready because gravel doesn’t need to dry or anything. You just have to make sure the gravel is leveled and then you are good to go.

Here’s a table that shows the price you have to pay for a gravel base depending on your hot tub size.

 Gravel Base DimensionsBase Price
Small Hot Tubs40 Square Feet Gravel Base$28
Medium Hot Tub65 Square Feet Gravel Base$45
Large Hot Tubs90-100 Square Feet Gravel Base $63-70

The price also depends on the gravel type. There are a lot of different gravel types that you can use on your hot tub. And, each of them has a different price.

For example, pea gravel costs $0.94 while normal gravel costs $0.70.  Some people decide to fill the hole with normal gravel, and then put pea gravel on top so it looks better. So, always check in with your local dealer to know the exact price.

Related Read: Can You Place a Hot Tub on a Deck?

How To Make a Gravel Hot Tub Base?

Here are the steps you need to take to build a gravel hot tub base:

1. Know Your Hot Tub Dimensions

Different hot tubs come in different dimensions and shapes. You have to know the exact dimensions of your hot tub before you build your gravel base. Check the manual or call the local store to know the dimensions.

However, if you don’t have access to those, here are the standard dimensions of a hot tub gravel base:

  • Small Hot Tub (35-square feet): You need a 40-square feet base.
  • Medium Hot Tub (60-square feet): You need a 65-square feet base.
  • Large Hot Tub (80-90-square feet): You need a 90-100-square feet base.

As mentioned before, you need to leave a space of a few inches all around the hot tub. That’s mostly done to avoid splash water to get into your grass, and for aesthetic purposes.

2. Check The Area

You have to check the area before you dig it. You have to make sure that there’s no overhead powerline. A hot tub should also not be placed near trees or tree roots.

A tree root will eventually grow and make the ground of your hot tub base unleveled. And, if you place the hot tub near a tree then the hot tub water will always be dirty.

Additionally, the hot tub base should be near a water source. You need to have a hose so you can re-fill the hot tub.  A power source should also be near the hot tub. But, at least 5 feet away.

3. Mark The Area

Now, you need to mark the ground. Use spray paint, or something that doesn’t come off easily, and mark the ground based on your dimensions.

The purpose of this is to know exactly the area that you will dig the hole. Basically, using spray paint you will make a square border on the ground.

4. Dig The Ground

Start by removing all the grass. You need to dig 6-inches into the ground. If you dig less than 6-inches you won’t be able to drain the hot tub on the gravel.

And, if you dig more than 6-inches then the gravel/base might become too soft and the hot tub can move.  You will have to dig 6-inches deep for the entire base.

Once you dig the entire base, use a level to check the ground/hole. The bare ground should be as level as possible before you add the gravel.

5. Fill Your Hole

There are different types of gravel you can use. I recommend using medium-grade construction gravel. You can eventually mix it with pea gravel.

If you want your backyard to look better, then fill 4-inches of the hole with medium-grade construction gravel and fill the remaining 2-inches with pea gravel.  Or, you can just fill the hole only with medium-grade construction gravel.

6. Level The Gravel

Before you place your hot tub on gravel, the ground should be level. We explained earlier that if the ground isn’t leveled then the hot tub will eventually crack. Use a shovel to level the gravel.

You can also step on the gravel and jump a few times just to see if the gravel is strong enough. After you are sure that the ground is leveled, then you place the hot tub on gravel. 

Can You Set Your Hot Tub on Pea Gravel?

Yes, you can set your hot tub on pea gravel. But, only if you used medium-grade construction gravel under the pea gravel.

Pea gravel isn’t strong enough to hold the entire weight of the hot tub alone. Pea gravel is softer than gravel, and if it’s not placed on a strong base then it can easily sink. That would make the entire ground un-leveled. And if the ground isn’t leveled then the hot tub will crack.

So, fill the hole with 4-inches of medium-grade construction gravel, and then for aesthetic purposes, you can fill the remaining 2-inches with pea gravel.

Related Read: Why Should You Use Pavers as a Hot Tub Base?

Can You Put an Inflatable Hot Tub on Gravel?

Because of the rough gravel surface, it’s not a good idea to place your inflatable hot tub directly into gravel. You have to put something under the inflatable hot tub.

The gravel base is strong enough to hold a regular hot tub that weighs 4000-6000 pounds. So, it can easily hold an inflatable hot tub that weighs way less.

But, you need to put something under the inflatable hot tub. As you might know, inflatable hot tubs are made of plastic. So, placing plastic on top of sharp rocks isn’t recommended. The gravel can pop the inflatable hot tub plastic.

You have to place something under the inflatable hot tub so the rocks don’t come in contact with the inflatable hot tub plastic body.

We recommend buying a spa pad or a spa floor mat to protect your inflatable hot tub from rocks. Spa pads are specially made to protect inflatable hot tubs when placed outdoors. Just make sure to find one that fits your inflatable hot tub dimensions.

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