How to Replicate Seawater at Home

By Kara Rae; Updated April 25, 2017
Sea water has a salinity of approximately 3.5 percent.

Home uses of seawater include such things as aquariums, holistic treatments and agriculture. Seawater is inexpensive and simple to produce. According to the Seafriends Marine Conservation and Education Center, seawater is a combination of salts mixed with water and gases. While the composition of seawater varies by geographic location, mixing sea salt with tap water most accurately duplicates it at home. Sea salt contains minerals directly from the sea and tap water contains abundant natural minerals like calcium.

Determine the quantity of seawater you wish to replicate.

Pour the tap water into a mixing container that is large enough to accommodate the quantity of seawater you are replicating. Allow the water to settle for approximately 10 minutes and come to room temperature.

Add the sea salt to the water, stirring slowly until completely dissolved. According to Sir Francis Drake High School, you will need approximately 35 grams of sea salt per liter of water or approximately 4 oz. of sea salt per gallon of water.


Sea salt is widely available at most grocery stores, but if you live near the sea, try evaporating seawater and using the fresh salt. If you choose to turn the homemade salt back into seawater, its chemical composition will be specific to the coast on which you live.


Drinking seawater will cause sickness and dehydration. Before engaging in any internal holistic cleanses, discuss the treatment with a practitioner.

Although you can use standard table salt to make salt water; sea salt allows for a more accurate replication of seawater.

Large-scale operations, like seawater agriculture, will require special storage and dispensing tanks for salt water.