Jess Stryker's Landscape Tutorial Series, Sprinklers & Irrigation.

Jess Stryker's
Irrigation Q&A

Water Source & Pumps

I anticipate purchasing oceanfront land and I am not sure if there is underground springs on the property. Is there a way to convert the ocean water for irrigation and human consumption?

Reverse osmosis filtration, however it is expensive and slow. For pumps and filtration you will likely spend over $500.00 for a system that purifies 10 or 15 gallons of water a day. Just enough for drinking. The price goes up from there.


I live on a large lake. I just built a new house and am planning the layout of my sprinkler system. Though I find your web sight very interesting, unless I missed something I didn't find any thing about pumping out of a large body of water. Please give me, and any of the other browsers out there who have the same situation any information about this.

The Pump Tutorial covers pump issues. Pumping from a lake is no different than pumping from a well except you need to filter the water and the intake pipe is a bit different. Most people want a dock anyway, so I usually install a dock or pier out into the lake then run put the pump intake on the end of the dock. The filter can go anywhere there is room.




Jess, when following your formulas exactly, I come up with a design flow of 12.6 gpm. After hooking up my main line and turning on the water, I let it run for 10 minutes to the ground outside and watching my pressure coming off the well tank I kept opening the valve until the pressure stabilized at 55 psi. I then checked the volume with a 5 gallon container and I'm getting 16 gpm. Should I change my design flow to match this or stick with the 12.6 I originally got?

You can use the 16 GPM figure. You measured it correctly. I don't normally tell people to do that because most of them screw up the process and get a false reading. The higher GPM you measured is because you pump is more efficient than the 55% the formula assumes. I would suggest maybe 14 or 15 GPM as a design goal to allow for a drop in efficiency as the pump gets older.




My primary interest is in analyzing a water well that exists on a piece of property in the Sierra's. Got some information from the person who dug the well
some time ago, but am taking it with a grain of salt. Have read your comments on wells, but can you direct me to a web site or a book or ? That would help in diagnosing what the well characteristics and issues might be? For example, if we turn the pump on for many hours to fill a 2800 gallon tank, what are the risks vs. the normal operation of the pump to fill a 50 gallon pressurization system?

First, I'm jealous! The Sierras are one of my favorite places, as I'm writing this I'm really looking forward to going cross-country skiing in Yosemite next weekend! But my favorite Sierra location is the section of The Lakes trail between the Watchtower and Heather Lake in Sequoia National Park At this location you're several hundred feet up the cliff above Tokopah Falls and looking out across the a huge granite valley with towering peaks in the background. The view fills your entire peripheral vision field on both sides. You have to hike a couple hours to get there, but I know of no comparable view on earth. You sit and look, but it is so overwhelming that you simply can't take it all in. So if you can handle a 5 to 6 hour moderately strenuous hike, and your not afraid of 1000' drop offs on the side of the trail, pack your bags and head to Sequoia. The trail is literally blasted into the side of a cliff in some places. Not for small children. The trail head is at the old Wolverton ski area (the ski area was removed years ago).

Unfortunately I don't know of any good books, info on wells is a bit scarce. Most of what I know was picked up here and there over the years. Wells in the Sierra are known for their lack of reliability. The major problem is that they are drilled into granite. Therefore the water must move to them through cracks in the rock. In the Sierras (and I suspect other mountain ranges as well) it is not unusual to drill a "dry hole", move the rig over 5 feet, and get a 100 GPM well. It all comes down to luck in hitting a major fault in the granite.

You can run that pump as long as you need to, provided it doesn't pump the well dry. Because Sierra wells have typically low volumes, the standard approach is to use a large storage tank, and pump water into the tank close to 24 hours a day. So your idea of a 2800 gallon tank is right on track. Then a second, higher volume "booster pump" pumps the water from the tank to the sprinkler system and or other uses. I have designed irrigation systems for several schools in the Sierras where we used this method. So the approach is slowly fill the tank, then quickly empty it for irrigation at night when the kids aren't around (or at least they aren't supposed to be around!). Most of the large projects I have worked on use tanks of 10,000 to 50,000 gallons for storage. A small submersible pump fills the tank, then a larger end suction centrifugal pump runs the sprinklers from the tank.

The bottom line is the well pump will actually hold up longer being run for long periods of time than it would under the stop and start usage typical of most wells. Much like a car driven on the freeway all day will last longer than one driven on short trips around town.


One thing I noticed though that can be a little misleading. in your well pump section, you talk about choosing the right pump for the sprinklers, but you should also mention that the pump can only be as big as the well can provide. E.g.. My well which is inactive but want to re-activate it for my sprinklers, apparently(according to the company who installed the well many years ago) can only supply 360 gallons/hour. Therefore it is useless for me to get a pump that takes in more than 6 gpm. I will test this myself hoping that the info I have was based on the pump and not the actual well. Or else I can't use my well it won't supply enough water unless putting a maximum of two large lawn area sprinkler heads per zone which use 3 gpm each. Just thought I would let you know that in your tutorial you should add when choosing your pump to verify the actual well capacity.

You are correct. If the well won't provide enough water the pump will pump it dry. For low capacity wells use a storage tank to store the water. See the question above this one for more information.




I have a well which has a submersible pump. In determining my drawdown level, I notice your diagram indicates the pump at the top of the well. Being a submersible, mine is located at the bottom of the well (242 feet down). Will I need to modify the calculations in any way to account for this?

No. It doesn't matter where the pump is.



Do you recommend connecting my irrigation system before or after my pressure tank? My well pump can handle the irrigation system by itself and I want to hook up before the pressure tank as to not affect the water pressure in my home.

You can hook up before most tanks. The bad news is that regardless of where you hook up the pressure in your house will be equally effected! The best reason for hooking up before the tank is to keep the irrigation water from flowing through the tank creating turbulence in the tank which might shorten the tank's life (hard to say if it really would shorten the tanks life, but that's the theory).

Some tanks have a built in check valve at the tank inlet. If the tank has a built in check valve the pressure switch will always be located on the tank or downstream (after) the tank. If the tank has a built in check valve and you plan to use the pressure switch to start the pump for the irrigation system you must tap in after the tank. If the pressure switch is between the well and the tank then there isn't a check valve in the tank and you can connect anywhere..


Here's the deal. I run off a 2hp pump in a well that goes into a pressure tank for the house... (edited, blah, blah, blah)

So one day I thought to myself, why not just use a booster pump to get the necessary pressure. I figure I will T off the underground water supply between the well and the pressure tank (which is in my house), then add a 1.5 or 2 hp booster pump and viola, I have the pressure I need.... (edited, blah, blah, blah)

So, here is my question. Once I put on the T and go to connect the booster pump, there will be a static pressure of somewhere in the neighborhood of 30-50psi at the point where the booster pump will be connected. At least, that's what the gauge on my pressure tank says. Granted there will be an elevation change and so on. The exact number isn't the issue. The issue is what will the final pressure be?

When I look at the pump literature it provides a neat concise table saying something like "at 50psi, such and such height of pump, 20gpm".

But is the "50 psi", in this example, ADDED to the already static 30-50psi giving me 80-100psi? Or is it just the final result whether I had 30 psi to begin with or I was just pumping out of a pond?

Yes, you add them together. So old pump pressure + booster pump pressure = final pressure.


I was wondering if you had advice on hooking up pressure tanks? ( bladder type ). I need to know how they work. and how to install a pressure switch. Or is there a site were I can learn this.

All I have is the tutorial on pumps. It briefly covers this. Your primary source needs to be the manufacturer of the tank and the switch as there are variables in installation by model. Generally it doesn't matter where you put the switch.


I need your help in determining my needs for a water well. I need a well since using city water is not cost effective. My problem is I am receiving conflicting information about it depending on who I talk to. Is a shallow well enough?, is a rock well an overkill?. And how do you decide.

I really don't have enough information to give you a definitive answer, however I can give you some generalities.

First, you need to know that it is illegal to install a well in most areas where there is a water company providing water. Why? Probably in part to prevent competition, but mostly it's for pollution control and to prevent over use of groundwater resources. So be sure to check on that as I would feel real bad if you were caught, and fined, and forced to "legally abandon" your new well (an often expensive process involving plugging the well, testing the plug, certifying it is done correctly, paying lots of fees, etc. The purpose of all this is to prevent surface water from running into old wells and polluting the ground water which everyone is drinking). OK, now back to your question.

Shallow wells are often used when the water is exclusively used for irrigation. The most common reason for not using shallow wells for any thing else is that the shallow water table is often polluted. Deeper wells are used to bore beneath the shallow, polluted water to reach clean drinking quality water. Some shallow water is not even suitable for use in irrigation, I'm assuming no reputable well driller would drill a well where it was not suitable, but it wouldn't hurt to have a water sample tested before the driller leaves the drill site. In fact it's not a bad idea for any well to have a water test run.

The other problem with shallow wells is reliability. Is the water supply reliable at shallow depths? Some shallow water is here today, gone tomorrow based on the weather. In dry years when you need irrigation most, the water isn't available. Your local geological survey office may be able to help with historical water depth data that will give an idea of water availability at various depths.

Hard rock wells can also have reliability problems. For example, in the Sierra foothills of California wells are a hit and miss business. A well can be drilled in one spot and come up dry. Move 10' over, drill another well and you can get an almost unlimited water supply. This is because the water travels through cracks in the granite rock. If you hit a crack with water your in luck. If you miss, tough luck! This is a common problem in mountainous areas.

Your best bet is to do some local research. The geological survey office would be a good place to start, they can probably point you to others who can help.



I have built a workshop near lake and would like to pump water to sink and hose bib for general use (not drinking). Do I need to treat the water?

Probably not, provided the lake water isn't contaminated with any harmful products. Codes require that all "non-potable" (the term used for non-drinking quality water) outlets be clearly marked with signs warning people not to drink the water or use it for other "domestic purposes" such as food preparation or washing hands prior to food preparation. Standard common sense stuff. Generally the codes will not allow the water to be piped to the interior of any buildings where it might be mistaken for safe water, so your sink would likely need to be outside. I'm not positive if a workshop would be considered "inside". There is also a industry standard that non-potable water outlets are painted purple to signify that the water is not suitable for drinking or food preparation.

When I was a kid my folks had a one room cabin on the Rogue River in Shady Cove, Oregon. All of our water came directly from the river. We chlorinated it and used it for pretty much everything except drinking. We all survived. Sorta. (For you locals who are wondering, the yellow cabin that was across from the school. It's long since gone. Yes, I'm that skinny kid who showed up in town every summer.)

You will probably want to have some sort of filter to take out stuff that might cause problems in the pipes and valves, such as algae, sand, etc. See the filtration tutorial for more info.



i am having a problem with a system that was already in place at the home that i bought. the motor was not there... so i took the one from my pool which was the same size.... as far as i know. everything fit perfect. anyways... i hooked it up and primed it and it got flowing pretty good then it would bog the motor down
and then speed up again... so it was going strong .... then weak..... then strong.... then weak.... all the heads are clear. but it seems to be burning
up the motor. and its not a constant flow. the motor is a 1 hp. motor. do you think that the motor isnt strong enough?

The pump must be properly sized for the irrigation system demand. Doesn't sound like its the right size to me...



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