How much fall do I need for gravity-fed water?

Every 2.31 feet of vertical drop gives you 1 psi. Around 90 feet of fall delivers roughly 40 psi at the house before friction losses.

Is spring water safe to drink?

Not by default. Develop the spring properly, then test for coliform and nitrates, and run sediment plus UV treatment before the tap.

What flow rate does a household need?

A family of four is comfortable on a spring producing one gallon per minute continuously, given adequate storage.

Spring Water Systems

Developing a Mountain Spring for Gravity-Fed Water

Nine years, no pump, 43 psi at the barn. The full build: finding the vein, boxing it, and getting the water downhill clean.

15 min read AdvancedApril 11, 2026

Stone spring box in a mossy forest hollow with pipe running to a cistern

Gravity is the only pump that never fails, never needs power and never wakes you at 2 a.m. If you have fall on your land and a spring, you have the best water system money can buy for about a thousand dollars.

This is the second spring we developed on this property, documented from the first shovel.

Materials

Spring box with lid
Screened stainless intake
Overflow and drain assembly
300 ft of 1in HDPE
Washed gravel
Bentonite clay

Tools

Mattock and shovel
Trencher or mini excavator
Pressure gauge
Pipe fusion or barb fittings
Level

Estimated cost: $1,250. Difficulty: Advanced.

1.Find the vein, not the seep

Water surfacing on a hillside has usually traveled sideways. Dig uphill from the wet spot until you hit the point where water emerges from rock or a gravel seam under pressure. That is what you box — a seep boxed at the surface will silt in and go bad.

Excavated hillside showing water emerging from a gravel seam

2.Flow-test in the driest month

Time a five-gallon bucket in late August. Even a half gallon per minute is 720 gallons a day, far more than a household uses. Design around the dry-season number and you will never run short.

3.Set the spring box with a clean water path

Bed the box in washed gravel, take the intake off the upstream face through a 40-mesh stainless screen, and cap the whole excavation with bentonite clay so surface runoff cannot reach the collection zone. Overflow and cleanout on the downhill face.

4.Calculate head and size the pipe

Every foot of fall gives you 0.433 psi. Our box sits 108 feet above the barn — 46.7 psi static, minus about 4 psi friction loss over 300 feet of 1-inch line at our flow rate. Undersize the pipe and you throw away pressure you can never get back.

5.Bury deep and protect the source

Below frost depth, on a continuous downhill grade, with no high points to trap air. Fence livestock out of the collection area entirely, and test the water annually for coliform whether or not it tastes fine.

Common questions

How much fall do I need for gravity-fed water?: Every 2.31 feet of vertical drop gives you 1 psi. Around 90 feet of fall delivers roughly 40 psi at the house before friction losses.
Is spring water safe to drink?: Not by default. Develop the spring properly, then test for coliform and nitrates, and run sediment plus UV treatment before the tap.
What flow rate does a household need?: A family of four is comfortable on a spring producing one gallon per minute continuously, given adequate storage.

Written by

Ellis Hartwell

Twelve years building and rebuilding systems on 28 mountainside acres. Everything published here has run on this property or been documented on site with the owners.

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