When you don’t have municipal water to rely on, your water well becomes a critical factor. Domestic water wells, also called residential water wells, or private water wells, provide the water needed for daily living – drinking, cooking, washing people, washing clothes, and the like. The private water well may also provide water for gardening or landscaping.
Let’s take a closer look at the domestic water well. We’ll also look briefly at the pumps used to move water from the well to the point of use.
Like many states, California places a premium on maintaining and preserving groundwater. Because of this, the state and some localities place restrictions on building wells and regulations and standards for building, maintaining, and decommissioning wells.
As a consumer, you may not be aware of all the requirements, but your Marin County well contractor should be. When you speak with your contractors, you will benefit from a little background on groundwater, wells and pumps, and constructions practices.
Use the articles below to get insight into what it takes to build a well. With these articles as an overview, you’ll feel more comfortable discussing the well-building process and pump installation with your contractor.
Groundwater is Precious in Marin County
California rises and falls by its water supply. Whether you live in San Rafael, Novato, Mill Valley, San Anselmo, Larkspur, or in smaller areas like Kentfield, Lucas Valley, or Santa Venetia, it’s important to protect the groundwater.
The water that your well will provide is part of the groundwater supply in California. Groundwater appears only in the saturation zone. It is the water – from precipitation, or from nearby lakes, for example – that exists in the spaces between soil particles, rock cracks and the like. The saturation zone lies well beneath the earth’s surface and is filled, or saturated, with water. The water table is the upper surface of the saturation zone and is affected by atmospheric pressure.
Digging to the water table means digging to the point where the earth is saturated with water. Within the saturation zone, you may find aquifers. An aquifer is any underground formation – perhaps formed by rock, or by any geological structures – that can store water that wells can access. So ideally your well will tap into an aquifer to produce water.
Locating Your Well in Marin County
Think about your well even before you buy land. If you are considering buying a property with no well or other water source, talk to the realtor, neighbors, well construction companies in the area, and anyone else who can give insight into local water conditions. Their knowledge, along with any knowledge you can get from topographical reports, geological surveys, and the like, can help you determine if there is a possibility of finding sufficient water to support you.
Of course, this approach works better in the lowlands. In the hills and mountains, finding water can be more difficult and even less predictable than in the lowlands. Of course, no well construction firm can guarantee to find water, no matter how good their local knowledge is.
The next step is to consider where to place the well. You and your contractor should discuss this. Be aware that there are further restrictions, including how close you can build your well to existing facilities. For example, the well must be a specified distance from sewage tanks, from animal pastures, from graveyards, and other potential contaminants.
Your well drilling contractor should be aware of these distances. You can also find California well standards at the Department of Water Resources site. Keep these regulations in mind, but try to place your well as close as possible to the point of use so that you can minimize the distance the water has to travel. The well should be at the highest gradient or you will have to improve the gradient so that surface water always drains away from the well.
You need to look for a water source that will produce enough water for your needs. The recommended amount of water is a pumping rate between 1 gallon per minute (gpm) and 5 gpm. This wide range reflects the varied conditions in California. Some in the mountains make do with 1 gpm.
There are several ways to estimate how much water you need. One technique is to count the number of fixtures in the house, and calculate 1 gpm per fixture. For example, the bathroom contains a sink, a tub with a faucet, and a showerhead. These count as three fixtures. The other method is to determine the peak flow required over seven minutes, either in the morning or at night, when all the family is home and using water. These methods do not include water for landscaping or gardening. As a guideline, a typical three to four bedroom house uses 8 gpm to 12 gpm.
Consult your power company to see if there are buried power lines near where you plan to dig. Also check for trees or power lines that could potentially be damaged by the equipment used to drill the well.
Constructing the Well in Marin County
Wells in San Anselmo, Mill Valley, Larkspur, San Rafael, Novato, or Kentfield, Lucas Valley, or Santa Venetia all share some construction similarities. Let’s examine these so you can have a reasonable conversation with your contractor or potential contractor.
A well can be dug using different methods – any method when properly implemented should result in a usable, standards-compliant well. In California, most wells are dug using rotary, reverse rotary, air rotary, and cable tool techniques. Different methods are used for different landscapes and for different purposes; for example, some techniques only work to build shallow wells. Some methods – for example, cable tool drilling - might take longer than other methods – e.g. rotary drilling.
In addition, rotary drilling and reverse rotary drilling need lots of water during the drilling process and a place to send out the muddy result, which will be a consideration if no water is available in the location.
As a consumer, though, you don’t need to worry too much about choosing the method of creating your well. Your contractor will probably choose the method based on his or her equipment, the land’s composition, and the depth of well needed. You should not concern yourself too much about this, as long as the equipment is in good repair so there are no breakdowns.
Well construction begins with a borehole – the hole cut into the ground. As the contractor drills, drill cuttings will emerge from the hole. The contractor must take note of these in a well log. For the contractor, part of the reason for keeping the log is to know what kind of cuttings emerge from the hole and the amount and quality of water coming out of the hole. Knowing the composition of the cuttings – whether the surrounding material is coarse or fine, for example - will help in the well design.
The well log will eventually be given to the owner and a copy must be registered with the state. The Department of Water Resources maintains a well completion log for all wells in California.
Once the hole is created, the well itself is constructed. Depending on what the contractor learns from boring the hole, well screens are placed in the hole, in combination with casing. The screen is designed to let water in and keep particles out. It has openings calibrated to the surrounding material to prevent that material from entering the well and clogging the pump.
The walls of the well are called the casing – a tube inserted into the hole through which the water will flow up to the surface. The tube may be steel, or plastic, among other materials. Depending on the local geology, the well screen and casing may be surrounded by a gravel pack. This pack acts as an additional filter before water enters the screen.
Once the casing and screens are installed the well must be sealed. The casing is smaller than the borehole. The area between the outer wall of the casing and the inner walls of the borehole is called the annulus or annular space. It is filled with cement and bentonite to a regulated depth to prevent contaminants from entering. This filling in of the annulus is also called grouting.
Next, the well needs to be developed. The contractor uses some method such as forcing water or air through the well to clear the well of any particles left over from construction. Good development extends the life of the well and of the pump, since contaminants can obstruct and damage the pump. Once the well is developed, the contractor should do a pump test, also called an aquifer test.
This test determines how much water is readily available from the well. The test pumps water at different rates over time and measures how much the water level in the well changes. The test results include pump rate and water level information that you will need to size your pump.
At this point, the contractor should inspect the well – some contractors have cameras they can drop down the well to see the sides of the well. A final well seal is installed. A pump and, typically, a water storage system, are installed. If you want your water to run to the house automatically, then you will likely need at least a storage tank. A pressurized storage tank includes compressed air and water.
Ideally, there should be a barrier between the water and the air, so that the water does not absorb the air. This tank provides a certain amount of storage, but mostly it takes advantage of the compressed air to help push the water through the pipes. In some cases, the tank becomes waterlogged – that is, the air does get absorbed and the tank completely fills with water. In this case, the pump will continue to operate continuously, which is not good for its extended life.
Searching Out the Right Qualifications for Well Drilling Services in Marin County
With a basic knowledge of what well building entails, you’ll be able to search out the right contractor. Whether you are creating your well in San Rafael, Novato, San Anselmo, Larkspur, or Mill Valley, or in Kentfield, Lucas Valley, or in Santa Venetia, check to see if you need a permit. Many areas in California require a permit before you can dig or modify an existing a well.
To see if you live in such an area, check with the Department of Water Resources on their website to see if a well-permitting agency exists for your region or city. If it does, you will need to obtain a permit before you can start your well.
California requires a contractor’s license for well builders. Moreover, it requires that those who construct wells have a C57, the specific license for a water well drilling contractor. Once your well is constructed, you will need a pump. Installing a pump also requires a specifically licensed contractor, most often a C61. The C61 specialty license includes subcategory D21 for machinery and pumps.
Some well water contractors in Marin County also sell and install pumps for your well, while others will refer you to a pump contractor. No matter whether you go with a single firm or with multiple firms, make sure each is properly and currently licensed for what they are doing. You can check license status at the Department of Consumer Affairs, Contractors’ State License Board site.
The License is the Starting Point for Finding a Good Contractor in Marin County
Do check that your contractor has a valid, current license. Don’t stop there. It’s a good idea to ask around for recommendations. Especially when looking for water, local knowledge can be invaluable. You’ll want someone who has earned a good reputation for knowing the region. You should also check to see if there is a physical location for the contractor. If you can only get your contractor on a cell phone, you might encounter some frustration.
Workers compensation insurance is mandatory in California for any company with employees. Check that your contractor carries it. Ask if your contractor has general liability insurance. General liability insurance is not mandatory. If the contractor does not have general liability insurance, you can ask them how they will take care of any losses from damage to property that would usually be covered by insurance. If they cannot cover such costs, you or your insurance may have to.
Verify that your contractor is bonded, since a California contractor must also have a contractor’s license bond. Be aware though, that the bond is a minimal amount and may not cover all the costs of any work that does not meet local codes. Also, the mere fact of being bonded does not provide any guarantee of the contractor’s abilities.
Your pump contractor may or may not be the same firm as your well contractor. Sometimes firms will do both, but they must be licensed for both. Sometimes the well vendor can refer you to a pump vendor. It’s important to be aware that you cannot know what pump you need for your well until you have had the well drilled and the pump test performed.
The pump size depends on how much work it has to do to extract water, so you need the results of the pump test. Be wary of anyone who tries to sell you a pump before you have performed the pump test.
Avoid any contractor unwilling to provide a detailed, written estimate. The estimate should not be a lump sum. It should itemize categories of services and materials.
The contract should include:
Charges by unit:
Materials (gravel pack, sealant, etc) by unit
Services – grouting, test pump per hour, developing per hour
Drilling per foot
Casing per foot
- Casing material and diameter. The casing material – steel, plastic, etc. – should be defined as well as the diameter and thickness. The diameter will be based on the expected amount of water from the well.
- Size of the well hole. There are standards for the diameter between the casing and the borehole wall, based on the method of drilling. Your contract should specify both the method of drilling and the borehole size.
- Estimated depth of well. You cannot guarantee where water will be found, but you can decide with your contractor in advance on an estimate.
- Sealing the annulus. Again, the space between the casing and borehole wall should be sealed. The contract should state how deep within in the well this sealing goes, based on the standards for the well type and circumstances.
- Well development. Cleans the well of dirt and other particles.
- Pump test.
- Intake section. Where water actually enters the well. The contract should state the type and diameter of the material used – for example, screens or perforated casing.
- Well completion report.
- If included, water testing services.
- If included, the pump, water storage supplies, pump power source, and anything else related to the water system.
- Guarantee. The contractor can provide good workmanship and materials. Of course, there can be no guarantee that you will strike water or that the water will be of good quality.
Since you are not dealing with a precise situation, you may come across situations where modifications to the contract are necessary. You should discuss these with your contractor and understand them. In a few cases, the changes may be significant enough to warrant a new contract.
Bringing Up Well Water in Marin County
Whether your well sits in San Anselmo, Novato, San Rafael, Larkspur, or Mill Valley, or in Lucas Valley, Santa Venetia, or Kentfield, a pump is usually required to bring water to the land surface. The most common kinds of pumps are submersible pumps and jet pumps.
The kind of pump you need will depend on the depth of water in your well. A submersible is very common in California. You will find some discussions of two-wire or three-wire pumps. In a two-wire pump, the controls are built in. In a three-wire pump, you need a separate control box. Jet pumps are sometimes classified as shallow well (25 feet or less) and deep well (25-110 feet). Most people install pumps that run on electricity. There are alternatives available, including solar, air-driven, and manual.
When you determine which pump to buy, you or your contractor will need to know the following:
- Casing material and thickness
- Distance from the top of the well to the waterline (the water’s surface)
- Water use – for household only, or for other uses
- Elevation between pump and point of use
- Casing material and thickness
- Pipes – what kind and what diameter and thickness
- Distance water must travel from well
Pumps are sold by capacity, measured in gallons per minute. It’s important not to get a pump that is more powerful than you need, since this inefficiency will raise energy costs. Your pump contractor should help you determine the other pieces you need to complete your pump and water system. These may include switches, valves, and power sources. Valves may be particularly important to prevent backflow into your well.
Well Maintenance and Eventual Destruction in Marin County
No matter where you live in Marin County, whether in San Anselmo, Larkspur, Mill Valley, Novato, San Rafael, Kentfield, Lucas Valley, or Santa Venetia, your well requires maintenance to stay in peak condition. Good well maintenance can include keeping a well log, which records information over time. Typical maintenance includes:
- Record the water level (from the ground to the top of the water surface) twice a year. Spring and fall are often recommended. This will give you a picture of water availability. It might vary with the seasons.
- Pump test once in a while – maybe every two years. Some utilities will perform a pump test. Take note of any changes in pump capacity.
- Water quality. Test if you notice significant changes in your water. Test for bacteria annually, and for chemical quality every five years.
- Clean the well, especially after work or repairs on the well.
If you need to modify your well at any time, you will need a permit. When a well is no longer producing or will not be used any more, the state requires that it be destroyed by a licensed well contractor. The well destruction must be reported to the state. The destruction typically involves sealing the well to prevent contaminants from getting into the groundwater.
Quality Testing the Water from Your Marin County Well
Finding water is not enough. You must also test the water for its quality and safety. You should first test as the well is being dug, then test regularly over time. You should determine with your contractor who will be responsible for the water quality testing. The water sample should be tested by a state-certified laboratory.
You can find information on certified laboratories and related information on the Environmental Laboratory Accreditation Program website from the California Department of Public Health. Based on the findings, you may want to add pieces to your water system, such as water softeners.View/Print