Cistern questions!
Clear all

Cistern questions!

Posts: 2
New Member
Topic starter

 Hello, my name is David. I am planning on relocating to St. Thomas.  this spring. I going to build my own house. The house will be able to sleep up to 8 people but will most likely only have 4 to 6 people there at a time.  What would people recommend as a size for the cistern? I am struggling to find any information on how big of a tank you should have. Also if anybody could refer me to a company that builds/ constructs Cisterns that would be a huge help as I am struggling to find information here in Chicago right now.

ps. Also if anyone has recommendations for a septic company!! That would be amazing!!

Posted : January 30, 2019 3:58 pm
Posts: 723
Honorable Member

I would say cistern size in gallons for a home should be approximately 10x the square footage of the house. So if the home is 2000 sq ft, the  cistern capacity should be about 20,000 gallons. 

The contractor who builds the home also builds the cistern. Normally the home sits on top of the cistern.  Also  your contractor should take care of subletting the septic system/tank. 




Posted : January 30, 2019 6:03 pm
Exit Zero
Posts: 2460
Famed Member

Yhe size will also need to reflect the part of the island you are building on, here on top of Crown Mt I have never bought water in 39 years in this house and it overflows a few times a year.

4 bdrm,2 bath,18,000gal. 3-6 full time residents.

on the east end or South side you may have to have a bigger cistern, or plan on trucking water.

Also - are the people living there? and conscious of  water conservation OR vacationing and have little concept of the cistern water storage idea. Big difference!

will you have to fill a pool  because of evaporation?

are the plans for the house accounting for the roof area Sq. Ft. and gutter collection, and allow for ease of access for cleaning and screening. Collecting every drop is important!

Always turn off any outside hoses if not in use - a split hose may drain the cistern while you are gone for the day.

a visual or quiet audible alarm that allows you to KNOW when the water pump is drawing water is a fine addition too.

You might consider a separate grey water cistern that collects off the driveway and is plumbed to flush the toilets, use for gardening, pressure washing etc - a great saving.


Posted : January 30, 2019 6:29 pm
Posts: 2433
Noble Member

I think your building permit from DPNR will have minimum cistern requirements as well.

Posted : January 31, 2019 2:06 am
Posts: 1048
Noble Member

A local, licensed architect, will be able to help you understand not only the code but also be able to help you with the size cistern you will need to meet the demand you will have as well as what kind of rainfall you might see in the area of your lot.  Exit Zero makes excellent points.  Generally speaking, bigger is usually better.  Because even if the home is owner-occupied and conservative with water if you ever sell the house it'd be nice to have a big enough cistern to accommodate a potential buyer who plans to short term rent the dwelling.  Your local contractor builds the cistern and septic or sub it out.  Most contractors have a core set of subcontractors they tend to work with.  

Posted : January 31, 2019 3:55 am
Search this website Type then hit enter to search
Close Menu